Attachment 341904 Details for Bug 186269 – Hacky patch

[patch] Hacky patch

reftokens.patch (text/plain), 212.81 KB, created by Simon Fraser (smfr) on 2018-06-04 08:23:57 PDT

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Creator: Simon Fraser (smfr)

Created: 2018-06-04 08:23:57 PDT

Size: 212.81 KB

patch

obsolete

>commit 1de9925e791d747c5ad8db6a154e0f7319e593bc
>Author: Simon Fraser <simon.fraser@apple.com>
>Date:   Sun Jun 3 22:16:38 2018 -0700
>
>    RefToken tracking
>
>diff --git a/Source/JavaScriptCore/API/JSContextRef.cpp b/Source/JavaScriptCore/API/JSContextRef.cpp
>index 025eba4e99c..4246b580c2c 100644
>--- a/Source/JavaScriptCore/API/JSContextRef.cpp
>+++ b/Source/JavaScriptCore/API/JSContextRef.cpp
>@@ -81,7 +81,7 @@ void JSContextGroupRelease(JSContextGroupRef group)
>     VM& vm = *toJS(group);
> 
>     JSLockHolder locker(&vm);
>-    vm.deref();
>+    vm.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> static bool internalScriptTimeoutCallback(ExecState* exec, void* callbackPtr, void* callbackData)
>@@ -179,7 +179,7 @@ void JSGlobalContextRelease(JSGlobalContextRef ctx)
>     bool protectCountIsZero = Heap::heap(exec->vmEntryGlobalObject())->unprotect(exec->vmEntryGlobalObject());
>     if (protectCountIsZero)
>         vm.heap.reportAbandonedObjectGraph();
>-    vm.deref();
>+    vm.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSObjectRef JSContextGetGlobalObject(JSContextRef ctx)
>diff --git a/Source/JavaScriptCore/API/JSObjectRef.cpp b/Source/JavaScriptCore/API/JSObjectRef.cpp
>index d80a070b7ab..d36d0ec6b17 100644
>--- a/Source/JavaScriptCore/API/JSObjectRef.cpp
>+++ b/Source/JavaScriptCore/API/JSObjectRef.cpp
>@@ -79,7 +79,7 @@ JSClassRef JSClassRetain(JSClassRef jsClass)
> 
> void JSClassRelease(JSClassRef jsClass)
> {
>-    jsClass->deref();
>+    jsClass->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSObjectRef JSObjectMake(JSContextRef ctx, JSClassRef jsClass, void* data)
>diff --git a/Source/JavaScriptCore/API/JSScriptRef.cpp b/Source/JavaScriptCore/API/JSScriptRef.cpp
>index 33f59a36334..cdb34f99649 100644
>--- a/Source/JavaScriptCore/API/JSScriptRef.cpp
>+++ b/Source/JavaScriptCore/API/JSScriptRef.cpp
>@@ -139,7 +139,7 @@ void JSScriptRetain(JSScriptRef script)
> void JSScriptRelease(JSScriptRef script)
> {
>     JSLockHolder locker(&script->vm());
>-    script->deref();
>+    script->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSValueRef JSScriptEvaluate(JSContextRef context, JSScriptRef script, JSValueRef thisValueRef, JSValueRef* exception)
>diff --git a/Source/JavaScriptCore/API/JSStringRef.cpp b/Source/JavaScriptCore/API/JSStringRef.cpp
>index 909540481da..44d3065f194 100644
>--- a/Source/JavaScriptCore/API/JSStringRef.cpp
>+++ b/Source/JavaScriptCore/API/JSStringRef.cpp
>@@ -73,7 +73,7 @@ JSStringRef JSStringRetain(JSStringRef string)
> 
> void JSStringRelease(JSStringRef string)
> {
>-    string->deref();
>+    string->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> size_t JSStringGetLength(JSStringRef string)
>diff --git a/Source/JavaScriptCore/API/JSWeakPrivate.cpp b/Source/JavaScriptCore/API/JSWeakPrivate.cpp
>index 246649f59e3..e35f0d99e14 100644
>--- a/Source/JavaScriptCore/API/JSWeakPrivate.cpp
>+++ b/Source/JavaScriptCore/API/JSWeakPrivate.cpp
>@@ -60,7 +60,7 @@ void JSWeakRelease(JSContextGroupRef contextGroup, JSWeakRef weakRef)
> {
>     VM* vm = toJS(contextGroup);
>     JSLockHolder locker(vm);
>-    weakRef->deref();
>+    weakRef->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSObjectRef JSWeakGetObject(JSWeakRef weakRef)
>diff --git a/Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.cpp b/Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.cpp
>index e7fc761dbed..b5d326db5f6 100644
>--- a/Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.cpp
>+++ b/Source/JavaScriptCore/bytecode/UnlinkedFunctionExecutable.cpp
>@@ -41,7 +41,9 @@
> 
> namespace JSC {
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(UnlinkedFunctionExecutable) <= 160, "UnlinkedFunctionExecutable should fit in a 160-byte cell. If you increase the size of this class, consider making a size class that perfectly fits it.");
>+#endif
> 
> const ClassInfo UnlinkedFunctionExecutable::s_info = { "UnlinkedFunctionExecutable", nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(UnlinkedFunctionExecutable) };
> 
>diff --git a/Source/JavaScriptCore/bytecode/Watchpoint.cpp b/Source/JavaScriptCore/bytecode/Watchpoint.cpp
>index 7ab385f585c..ad47ba603fb 100644
>--- a/Source/JavaScriptCore/bytecode/Watchpoint.cpp
>+++ b/Source/JavaScriptCore/bytecode/Watchpoint.cpp
>@@ -175,7 +175,7 @@ WatchpointSet* InlineWatchpointSet::inflateSlow()
> void InlineWatchpointSet::freeFat()
> {
>     ASSERT(isFat());
>-    fat()->deref();
>+    fat()->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> DeferredWatchpointFire::DeferredWatchpointFire(VM& vm)
>diff --git a/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
>index 651759f24ef..55fc31ba2ce 100644
>--- a/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
>+++ b/Source/JavaScriptCore/bytecompiler/BytecodeGenerator.cpp
>@@ -2292,14 +2292,14 @@ void BytecodeGenerator::popLexicalScopeInternal(VariableEnvironment& environment
>         VarOffset offset = symbolTableEntry.varOffset();
>         ASSERT(offset.isStack());
>         RegisterID* local = &registerFor(offset.stackOffset());
>-        local->deref();
>+        local->deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     if (hasCapturedVariables) {
>         RELEASE_ASSERT(stackEntry.m_scope);
>         emitPopScope(scopeRegister(), stackEntry.m_scope);
>         popLocalControlFlowScope();
>-        stackEntry.m_scope->deref();
>+        stackEntry.m_scope->deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     m_TDZStack.removeLast();
>@@ -2372,7 +2372,7 @@ void BytecodeGenerator::prepareLexicalScopeForNextForLoopIteration(VariableEnvir
>             RELEASE_ASSERT(!entry.isNull());
>             RegisterID* transitionValue = pair.first;
>             emitPutToScope(loopScope, variableForLocalEntry(identifier, entry, loopSymbolTable->index(), true), transitionValue, DoNotThrowIfNotFound, InitializationMode::NotInitialization);
>-            transitionValue->deref();
>+            transitionValue->deref(DEREF_DEFAULT_ARGUMENTS);
>         }
>     }
> }
>@@ -3840,7 +3840,7 @@ void BytecodeGenerator::emitPopWithScope()
>     emitPopScope(scopeRegister(), scopeRegister());
>     popLocalControlFlowScope();
>     auto stackEntry = m_lexicalScopeStack.takeLast();
>-    stackEntry.m_scope->deref();
>+    stackEntry.m_scope->deref(DEREF_DEFAULT_ARGUMENTS);
>     RELEASE_ASSERT(stackEntry.m_isWithScope);
> }
> 
>diff --git a/Source/JavaScriptCore/bytecompiler/Label.h b/Source/JavaScriptCore/bytecompiler/Label.h
>index 3e2d297f23d..462f83f50a2 100644
>--- a/Source/JavaScriptCore/bytecompiler/Label.h
>+++ b/Source/JavaScriptCore/bytecompiler/Label.h
>@@ -54,8 +54,12 @@ namespace JSC {
>             return m_location - opcode;
>         }
> 
>-        void ref() { ++m_refCount; }
>-        void deref()
>+        REF_RETURN_TYPE ref()
>+        {
>+            ++m_refCount;
>+            DEFAULT_REF_RETURN;
>+        }
>+        void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS)
>         {
>             --m_refCount;
>             ASSERT(m_refCount >= 0);
>diff --git a/Source/JavaScriptCore/bytecompiler/LabelScope.h b/Source/JavaScriptCore/bytecompiler/LabelScope.h
>index a94bf05ada4..11675687194 100644
>--- a/Source/JavaScriptCore/bytecompiler/LabelScope.h
>+++ b/Source/JavaScriptCore/bytecompiler/LabelScope.h
>@@ -56,8 +56,12 @@ public:
>     const Identifier* name() const { return m_name; }
>     int scopeDepth() const { return m_scopeDepth; }
> 
>-    void ref() { ++m_refCount; }
>-    void deref()
>+    REF_RETURN_TYPE ref()
>+    {
>+        ++m_refCount;
>+        DEFAULT_REF_RETURN;
>+    }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS)
>     {
>         --m_refCount;
>         ASSERT(m_refCount >= 0);
>diff --git a/Source/JavaScriptCore/bytecompiler/RegisterID.h b/Source/JavaScriptCore/bytecompiler/RegisterID.h
>index cc80f5eb891..86081191880 100644
>--- a/Source/JavaScriptCore/bytecompiler/RegisterID.h
>+++ b/Source/JavaScriptCore/bytecompiler/RegisterID.h
>@@ -97,12 +97,13 @@ namespace JSC {
>             return m_isTemporary;
>         }
> 
>-        void ref()
>+        REF_RETURN_TYPE ref()
>         {
>             ++m_refCount;
>+            DEFAULT_REF_RETURN;
>         }
> 
>-        void deref()
>+        void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS)
>         {
>             --m_refCount;
>             ASSERT(m_refCount >= 0);
>diff --git a/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp b/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp
>index 43bead62ff9..fb6861b2614 100644
>--- a/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp
>+++ b/Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp
>@@ -235,7 +235,7 @@ void LazyJSValue::emit(CCallHelpers& jit, JSValueRegs result) const
>             codeBlock->addConstant(realValue);
>             
>             if (thisValue.m_kind == NewStringImpl)
>-                thisValue.u.stringImpl->deref();
>+                thisValue.u.stringImpl->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>             linkBuffer.patch(label, realValue.asCell());
>         });
>diff --git a/Source/JavaScriptCore/heap/MarkingConstraint.cpp b/Source/JavaScriptCore/heap/MarkingConstraint.cpp
>index 3bab7679c55..bdcad0b4caf 100644
>--- a/Source/JavaScriptCore/heap/MarkingConstraint.cpp
>+++ b/Source/JavaScriptCore/heap/MarkingConstraint.cpp
>@@ -31,7 +31,7 @@
> 
> namespace JSC {
> 
>-static constexpr bool verboseMarkingConstraint = false;
>+static constexpr bool verboseMarkingConstraint = true;
> 
> MarkingConstraint::MarkingConstraint(CString abbreviatedName, CString name, ConstraintVolatility volatility, ConstraintConcurrency concurrency, ConstraintParallelism parallelism)
>     : m_abbreviatedName(abbreviatedName)
>@@ -57,7 +57,7 @@ void MarkingConstraint::execute(SlotVisitor& visitor)
>     executeImpl(visitor);
>     m_lastVisitCount += visitCounter.visitCount();
>     if (verboseMarkingConstraint && visitCounter.visitCount())
>-        dataLog("(", abbreviatedName(), " visited ", visitCounter.visitCount(), " in execute)");
>+        dataLog("(", name(), " visited ", visitCounter.visitCount(), " in execute)");
> }
> 
> double MarkingConstraint::quickWorkEstimate(SlotVisitor&)
>@@ -86,7 +86,7 @@ void MarkingConstraint::doParallelWork(SlotVisitor& visitor, SharedTask<void(Slo
>     VisitCounter visitCounter(visitor);
>     task.run(visitor);
>     if (verboseMarkingConstraint && visitCounter.visitCount())
>-        dataLog("(", abbreviatedName(), " visited ", visitCounter.visitCount(), " in doParallelWork)");
>+        dataLog("(", name(), " visited ", visitCounter.visitCount(), " in doParallelWork)");
>     {
>         auto locker = holdLock(m_lock);
>         m_lastVisitCount += visitCounter.visitCount();
>diff --git a/Source/JavaScriptCore/inspector/JSJavaScriptCallFrame.cpp b/Source/JavaScriptCore/inspector/JSJavaScriptCallFrame.cpp
>index a400425b851..57afe6c755e 100644
>--- a/Source/JavaScriptCore/inspector/JSJavaScriptCallFrame.cpp
>+++ b/Source/JavaScriptCore/inspector/JSJavaScriptCallFrame.cpp
>@@ -65,7 +65,7 @@ void JSJavaScriptCallFrame::destroy(JSC::JSCell* cell)
> void JSJavaScriptCallFrame::releaseImpl()
> {
>     if (auto impl = std::exchange(m_impl, nullptr))
>-        impl->deref();
>+        impl->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSJavaScriptCallFrame::~JSJavaScriptCallFrame()
>diff --git a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>index 3e894136b36..4b3b5aa3949 100644
>--- a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>+++ b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteConnectionToTargetCocoa.mm
>@@ -183,7 +183,7 @@ bool RemoteConnectionToTarget::setup(bool isAutomaticInspection, bool automatica
>                 RemoteInspector::singleton().updateTargetListing(targetIdentifier);
>             }
>         }
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> 
>     return true;
>@@ -213,7 +213,7 @@ void RemoteConnectionToTarget::close()
>                 RemoteInspector::singleton().updateTargetListing(targetIdentifier);
>             }
>         }
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> }
> 
>@@ -232,7 +232,7 @@ void RemoteConnectionToTarget::sendMessageToTarget(NSString *message)
> 
>             target->dispatchMessageFromRemote(message);
>         }
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> }
> 
>diff --git a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteInspectorXPCConnection.mm b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteInspectorXPCConnection.mm
>index cf00ba75c6b..b3801b43675 100644
>--- a/Source/JavaScriptCore/inspector/remote/cocoa/RemoteInspectorXPCConnection.mm
>+++ b/Source/JavaScriptCore/inspector/remote/cocoa/RemoteInspectorXPCConnection.mm
>@@ -164,7 +164,7 @@ void RemoteInspectorXPCConnection::handleEvent(xpc_object_t object)
>         if (object == XPC_ERROR_CONNECTION_INVALID) {
>             // This is the last event we will ever receive from the connection.
>             // This balances the ref() in the constructor.
>-            deref();
>+            deref(DEREF_DEFAULT_ARGUMENTS);
>         }
>         return;
>     }
>diff --git a/Source/JavaScriptCore/jit/JITStubRoutine.h b/Source/JavaScriptCore/jit/JITStubRoutine.h
>index 33d2a3673d7..ff88da8db36 100644
>--- a/Source/JavaScriptCore/jit/JITStubRoutine.h
>+++ b/Source/JavaScriptCore/jit/JITStubRoutine.h
>@@ -78,12 +78,13 @@ public:
>         return result;
>     }
>     
>-    void ref()
>+    REF_RETURN_TYPE ref()
>     {
>         m_refCount++;
>+        DEFAULT_REF_RETURN;
>     }
>     
>-    void deref()
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS)
>     {
>         if (--m_refCount)
>             return;
>diff --git a/Source/JavaScriptCore/jsc.cpp b/Source/JavaScriptCore/jsc.cpp
>index 4cbbb3d88ab..7df1f4f9e8c 100644
>--- a/Source/JavaScriptCore/jsc.cpp
>+++ b/Source/JavaScriptCore/jsc.cpp
>@@ -2750,7 +2750,7 @@ int runJSC(CommandLine options, bool isWorker, const Func& func)
>         JSLockHolder locker(vm);
>         // This is needed because we don't want the worker's main
>         // thread to die before its compilation threads finish.
>-        vm.deref();
>+        vm.deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     return result;
>diff --git a/Source/JavaScriptCore/parser/SourceProviderCacheItem.h b/Source/JavaScriptCore/parser/SourceProviderCacheItem.h
>index d0644d2df17..0447d9a986f 100644
>--- a/Source/JavaScriptCore/parser/SourceProviderCacheItem.h
>+++ b/Source/JavaScriptCore/parser/SourceProviderCacheItem.h
>@@ -109,7 +109,7 @@ private:
> inline SourceProviderCacheItem::~SourceProviderCacheItem()
> {
>     for (unsigned i = 0; i < usedVariablesCount; ++i)
>-        m_variables[i]->deref();
>+        m_variables[i]->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> inline std::unique_ptr<SourceProviderCacheItem> SourceProviderCacheItem::create(const SourceProviderCacheItemCreationParameters& parameters)
>diff --git a/Source/JavaScriptCore/runtime/HasOwnPropertyCache.h b/Source/JavaScriptCore/runtime/HasOwnPropertyCache.h
>index adadc89ab84..bbe08bb49f4 100644
>--- a/Source/JavaScriptCore/runtime/HasOwnPropertyCache.h
>+++ b/Source/JavaScriptCore/runtime/HasOwnPropertyCache.h
>@@ -39,12 +39,27 @@ public:
> 
>     struct Entry {
>         static ptrdiff_t offsetOfStructureID() { return OBJECT_OFFSETOF(Entry, structureID); }
>-        static ptrdiff_t offsetOfImpl() { return OBJECT_OFFSETOF(Entry, impl); }
>+        static ptrdiff_t offsetOfImpl() { return OBJECT_OFFSETOF(Entry, stringImpl); }
>         static ptrdiff_t offsetOfResult() { return OBJECT_OFFSETOF(Entry, result); }
> 
>-        RefPtr<UniquedStringImpl> impl;
>+        UniquedStringImpl* stringImpl;
>         StructureID structureID { 0 };
>         bool result { false };
>+        
>+        Entry(UniquedStringImpl* impl = nullptr, StructureID structID = 0, bool res = false)
>+            : stringImpl(impl)
>+            , structureID(structID)
>+            , result(res)
>+        {
>+            if (stringImpl)
>+                stringImpl->ref();
>+        }
>+
>+        ~Entry()
>+        {
>+            if (stringImpl)
>+                stringImpl->deref(DEREF_DEFAULT_ARGUMENTS);
>+        }
>     };
> 
>     HasOwnPropertyCache() = delete;
>@@ -74,7 +89,7 @@ public:
>         StructureID id = structure->id();
>         uint32_t index = HasOwnPropertyCache::hash(id, impl) & mask;
>         Entry& entry = bitwise_cast<Entry*>(this)[index];
>-        if (entry.structureID == id && entry.impl.get() == impl)
>+        if (entry.structureID == id && entry.stringImpl == impl)
>             return entry.result;
>         return std::nullopt;
>     }
>@@ -105,7 +120,7 @@ public:
>             UniquedStringImpl* impl = propName.uid();
>             StructureID id = structure->id();
>             uint32_t index = HasOwnPropertyCache::hash(id, impl) & mask;
>-            bitwise_cast<Entry*>(this)[index] = Entry { RefPtr<UniquedStringImpl>(impl), id, result };
>+            bitwise_cast<Entry*>(this)[index] = Entry(impl, id, result);
>         }
>     }
> 
>diff --git a/Source/JavaScriptCore/runtime/PropertyMapHashTable.h b/Source/JavaScriptCore/runtime/PropertyMapHashTable.h
>index f7d1f73ba52..3fb25d144ee 100644
>--- a/Source/JavaScriptCore/runtime/PropertyMapHashTable.h
>+++ b/Source/JavaScriptCore/runtime/PropertyMapHashTable.h
>@@ -387,7 +387,7 @@ inline void PropertyTable::remove(const find_iterator& iter)
>     // Replace this one element with the deleted sentinel. Also clear out
>     // the entry so we can iterate all the entries as needed.
>     m_index[iter.second] = deletedEntryIndex();
>-    iter.first->key->deref();
>+    iter.first->key->deref(DEREF_DEFAULT_ARGUMENTS);
>     iter.first->key = PROPERTY_MAP_DELETED_ENTRY_KEY;
> 
>     ASSERT(m_keyCount >= 1);
>diff --git a/Source/JavaScriptCore/runtime/PropertyTable.cpp b/Source/JavaScriptCore/runtime/PropertyTable.cpp
>index 59ec41c49ae..8631c26da8e 100644
>--- a/Source/JavaScriptCore/runtime/PropertyTable.cpp
>+++ b/Source/JavaScriptCore/runtime/PropertyTable.cpp
>@@ -119,7 +119,7 @@ PropertyTable::~PropertyTable()
> {
>     iterator end = this->end();
>     for (iterator iter = begin(); iter != end; ++iter)
>-        iter->key->deref();
>+        iter->key->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     fastFree(m_index);
> }
>diff --git a/Source/WTF/WTF.xcodeproj/project.pbxproj b/Source/WTF/WTF.xcodeproj/project.pbxproj
>index 1043b8d6223..5b73c93ba31 100644
>--- a/Source/WTF/WTF.xcodeproj/project.pbxproj
>+++ b/Source/WTF/WTF.xcodeproj/project.pbxproj
>@@ -32,6 +32,7 @@
> 		0F66B2901DC97BAB004A1D3F /* TimeWithDynamicClockType.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F66B2861DC97BAB004A1D3F /* TimeWithDynamicClockType.cpp */; };
> 		0F66B2921DC97BAB004A1D3F /* WallTime.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F66B2881DC97BAB004A1D3F /* WallTime.cpp */; };
> 		0F7075F51FBF53CD00489AF0 /* TimingScope.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F7075F41FBF537A00489AF0 /* TimingScope.cpp */; };
>+		0F77584620C502F200AB5A51 /* RefTracker.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F77584520C502F100AB5A51 /* RefTracker.cpp */; };
> 		0F7C5FB61D885CF20044F5E2 /* FastBitVector.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F7C5FB51D885CF20044F5E2 /* FastBitVector.cpp */; };
> 		0F824A681B7443A0002E345D /* ParkingLot.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F824A641B7443A0002E345D /* ParkingLot.cpp */; };
> 		0F8E85DB1FD485B000691889 /* CountingLock.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 0F8E85DA1FD485B000691889 /* CountingLock.cpp */; };
>@@ -217,6 +218,8 @@
> 		0F7075F31FBF537A00489AF0 /* TimingScope.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = TimingScope.h; sourceTree = "<group>"; };
> 		0F7075F41FBF537A00489AF0 /* TimingScope.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = TimingScope.cpp; sourceTree = "<group>"; };
> 		0F725CAB1C50461600AD943A /* RangeSet.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RangeSet.h; sourceTree = "<group>"; };
>+		0F77584520C502F100AB5A51 /* RefTracker.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = RefTracker.cpp; sourceTree = "<group>"; };
>+		0F77584720C502FE00AB5A51 /* RefTracker.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = RefTracker.h; sourceTree = "<group>"; };
> 		0F79C7C31E73511800EB34D1 /* FastTLS.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = FastTLS.h; sourceTree = "<group>"; };
> 		0F7C5FB51D885CF20044F5E2 /* FastBitVector.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = FastBitVector.cpp; sourceTree = "<group>"; };
> 		0F7EB85B1FA8FF4100F1ABCB /* IsoMalloc.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = IsoMalloc.h; sourceTree = "<group>"; };
>@@ -1036,6 +1039,8 @@
> 				A8A47302151A825B004123FF /* RefCountedLeakCounter.h */,
> 				86F46F5F1A2840EE00CCBF22 /* RefCounter.h */,
> 				A8A47303151A825B004123FF /* RefPtr.h */,
>+				0F77584720C502FE00AB5A51 /* RefTracker.h */,
>+				0F77584520C502F100AB5A51 /* RefTracker.cpp */,
> 				A8A47305151A825B004123FF /* RetainPtr.h */,
> 				2CDED0F118115C85004DBA70 /* RunLoop.cpp */,
> 				2CDED0F218115C85004DBA70 /* RunLoop.h */,
>@@ -1527,6 +1532,7 @@
> 				3337DB9CE743410FAF076E17 /* StackTrace.cpp in Sources */,
> 				A8A4743C151A825B004123FF /* StringBuilder.cpp in Sources */,
> 				E38D6E271F5522E300A75CC4 /* StringBuilderJSON.cpp in Sources */,
>+				0F77584620C502F200AB5A51 /* RefTracker.cpp in Sources */,
> 				A5BA15FB182435A600A82E69 /* StringCF.cpp in Sources */,
> 				A8A47440151A825B004123FF /* StringImpl.cpp in Sources */,
> 				A5BA15FC182435A600A82E69 /* StringImplCF.cpp in Sources */,
>diff --git a/Source/WTF/wtf/DeferrableRefCounted.h b/Source/WTF/wtf/DeferrableRefCounted.h
>index 796481a33cf..5047422467f 100644
>--- a/Source/WTF/wtf/DeferrableRefCounted.h
>+++ b/Source/WTF/wtf/DeferrableRefCounted.h
>@@ -42,9 +42,10 @@ class DeferrableRefCountedBase {
>     static const unsigned normalIncrement = 2;
> 
> public:
>-    void ref() const
>+    REF_RETURN_TYPE ref() const
>     {
>         m_refCount += normalIncrement;
>+        DEFAULT_REF_RETURN;
>     }
> 
>     bool hasOneRef() const
>@@ -72,7 +73,7 @@ protected:
>     {
>     }
> 
>-    bool derefBase() const
>+    bool derefBase(DEREF_ARGUMENT_TYPE) const
>     {
>         m_refCount -= normalIncrement;
>         return !m_refCount;
>@@ -96,9 +97,9 @@ template<typename T>
> class DeferrableRefCounted : public DeferrableRefCountedBase {
>     WTF_MAKE_NONCOPYABLE(DeferrableRefCounted); WTF_MAKE_FAST_ALLOCATED;
> public:
>-    void deref() const
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) const
>     {
>-        if (derefBase())
>+        if (derefBase(DEREF_ARGUMENT_NAME))
>             delete static_cast<const T*>(this);
>     }
> 
>diff --git a/Source/WTF/wtf/Ref.h b/Source/WTF/wtf/Ref.h
>index 3b3158dfb6e..7c74c1d3270 100644
>--- a/Source/WTF/wtf/Ref.h
>+++ b/Source/WTF/wtf/Ref.h
>@@ -39,10 +39,30 @@ extern "C" void __asan_unpoison_memory_region(void const volatile *addr, size_t
> extern "C" int __asan_address_is_poisoned(void const volatile *addr);
> #endif
> 
>+// Define ALLOW_REF_TRACING to enable debugging code that detects mismatched ref()/deref().
>+#define ALLOW_REF_TRACING 1
>+
>+#if ALLOW_REF_TRACING
>+#define REF_RETURN_TYPE WTF::RefToken
>+#define DEREF_ARGUMENT_TYPE WTF::RefToken
>+#define DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS WTF::RefToken = 0
>+#define DEREF_DEFAULT_ARGUMENTS 0
>+#define DEREF_ARGUMENT_NAME token
>+#define DEFAULT_REF_RETURN return 0
>+#else
>+#define REF_RETURN_TYPE void
>+#define DEREF_ARGUMENT_TYPE
>+#define DEREF_DEFAULT_ARGUMENTS
>+#define DEREF_ARGUMENT_NAME
>+#define DEFAULT_REF_RETURN return
>+#endif
>+
> namespace WTF {
> 
> inline void adopted(const void*) { }
> 
>+typedef unsigned RefToken;
>+
> template<typename T, typename PtrTraits> class Ref;
> template<typename T, typename PtrTraits = DumbPtrTraits<T>> Ref<T, PtrTraits> adoptRef(T&);
> 
>@@ -58,12 +78,19 @@ public:
>             __asan_unpoison_memory_region(this, sizeof(*this));
> #endif
>         if (m_ptr)
>-            PtrTraits::unwrap(m_ptr)->deref();
>+            PtrTraits::unwrap(m_ptr)->deref(
>+#if ALLOW_REF_TRACING
>+                m_token
>+#endif
>+            );
>     }
> 
>     Ref(T& object)
>         : m_ptr(&object)
>     {
>+#if ALLOW_REF_TRACING
>+        m_token =
>+#endif
>         object.ref();
>     }
> 
>@@ -73,6 +100,9 @@ public:
> 
>     Ref(Ref&& other)
>         : m_ptr(&other.leakRef())
>+#if ALLOW_REF_TRACING
>+        , m_token(other.token())
>+#endif
>     {
>         ASSERT(m_ptr);
>     }
>@@ -80,6 +110,9 @@ public:
>     template<typename X, typename Y>
>     Ref(Ref<X, Y>&& other)
>         : m_ptr(&other.leakRef())
>+#if ALLOW_REF_TRACING
>+        , m_token(other.token())
>+#endif
>     {
>         ASSERT(m_ptr);
>     }
>@@ -139,6 +172,11 @@ public:
>         return result;
>     }
> 
>+#if ALLOW_REF_TRACING
>+    RefToken token() const { return m_token; }
>+    void setToken(RefToken token) { m_token = token; }
>+#endif
>+
> private:
>     friend Ref adoptRef<T>(T&);
>     template<typename X, typename Y> friend class Ref;
>@@ -146,10 +184,16 @@ private:
>     enum AdoptTag { Adopt };
>     Ref(T& object, AdoptTag)
>         : m_ptr(&object)
>+#if ALLOW_REF_TRACING
>+        , m_token(0)
>+#endif
>     {
>     }
> 
>     typename PtrTraits::StorageType m_ptr;
>+#if ALLOW_REF_TRACING
>+    RefToken m_token;
>+#endif
> };
> 
> template<typename T, typename U> Ref<T, U> adoptRef(T&);
>@@ -193,6 +237,9 @@ template<typename X, typename Y>
> inline void Ref<T, U>::swap(Ref<X, Y>& other)
> {
>     U::swap(m_ptr, other.m_ptr);
>+#if ALLOW_REF_TRACING
>+    std::swap(m_token, other.m_token);
>+#endif
> }
> 
> template<typename T, typename U, typename X, typename Y, typename = std::enable_if_t<!std::is_same<U, DumbPtrTraits<T>>::value || !std::is_same<Y, DumbPtrTraits<X>>::value>>
>diff --git a/Source/WTF/wtf/RefCounted.h b/Source/WTF/wtf/RefCounted.h
>index 13762e07aef..74d5b7417fa 100644
>--- a/Source/WTF/wtf/RefCounted.h
>+++ b/Source/WTF/wtf/RefCounted.h
>@@ -23,6 +23,7 @@
> #include <wtf/Assertions.h>
> #include <wtf/FastMalloc.h>
> #include <wtf/Noncopyable.h>
>+#include <wtf/Ref.h>
> 
> namespace WTF {
> 
>@@ -37,13 +38,14 @@ namespace WTF {
> // generated by the compiler (technique called template hoisting).
> class RefCountedBase {
> public:
>-    void ref() const
>+    REF_RETURN_TYPE ref() const
>     {
> #if CHECK_REF_COUNTED_LIFECYCLE
>         ASSERT_WITH_SECURITY_IMPLICATION(!m_deletionHasBegun);
>         ASSERT(!m_adoptionIsRequired);
> #endif
>         ++m_refCount;
>+        DEFAULT_REF_RETURN;
>     }
> 
>     bool hasOneRef() const
>@@ -87,7 +89,7 @@ protected:
>     }
> 
>     // Returns whether the pointer should be freed or not.
>-    bool derefBase() const
>+    bool derefBase(DEREF_ARGUMENT_TYPE) const
>     {
> #if CHECK_REF_COUNTED_LIFECYCLE
>         ASSERT_WITH_SECURITY_IMPLICATION(!m_deletionHasBegun);
>@@ -139,9 +141,9 @@ inline void adopted(RefCountedBase* object)
> template<typename T> class RefCounted : public RefCountedBase {
>     WTF_MAKE_NONCOPYABLE(RefCounted); WTF_MAKE_FAST_ALLOCATED;
> public:
>-    void deref() const
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) const
>     {
>-        if (derefBase())
>+        if (derefBase(DEREF_ARGUMENT_NAME))
>             delete static_cast<const T*>(this);
>     }
> 
>diff --git a/Source/WTF/wtf/RefCounter.h b/Source/WTF/wtf/RefCounter.h
>index 26e11f47d95..d031484135c 100644
>--- a/Source/WTF/wtf/RefCounter.h
>+++ b/Source/WTF/wtf/RefCounter.h
>@@ -42,8 +42,8 @@ class RefCounter {
>     class Count {
>         WTF_MAKE_NONCOPYABLE(Count);
>     public:
>-        void ref();
>-        void deref();
>+        REF_RETURN_TYPE ref();
>+        void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>         void refCounterWasDeleted();
> 
>@@ -84,15 +84,17 @@ private:
> };
> 
> template<typename T>
>-inline void RefCounter<T>::Count::ref()
>+inline REF_RETURN_TYPE RefCounter<T>::Count::ref()
> {
>     ++m_value;
>     if (m_refCounter && m_refCounter->m_valueDidChange)
>         m_refCounter->m_valueDidChange(RefCounterEvent::Increment);
>+
>+    DEFAULT_REF_RETURN;
> }
> 
> template<typename T>
>-inline void RefCounter<T>::Count::deref()
>+inline void RefCounter<T>::Count::deref(DEREF_ARGUMENT_TYPE)
> {
>     ASSERT(m_value);
> 
>diff --git a/Source/WTF/wtf/RefPtr.h b/Source/WTF/wtf/RefPtr.h
>index 522085353b8..3cea6145c88 100644
>--- a/Source/WTF/wtf/RefPtr.h
>+++ b/Source/WTF/wtf/RefPtr.h
>@@ -33,6 +33,21 @@ namespace WTF {
> template<typename T, typename PtrTraits> class RefPtr;
> template<typename T, typename PtrTraits = DumbPtrTraits<T>> RefPtr<T, PtrTraits> adoptRef(T*);
> 
>+#if ALLOW_REF_TRACING
>+template<typename T> ALWAYS_INLINE RefToken refIfNotNull(T* ptr)
>+{
>+    if (LIKELY(ptr != nullptr))
>+        return ptr->ref();
>+    
>+    return 0;
>+}
>+
>+template<typename T> ALWAYS_INLINE void derefIfNotNull(T* ptr, RefToken token = 0)
>+{
>+    if (LIKELY(ptr != nullptr))
>+        ptr->deref(token);
>+}
>+#else
> template<typename T> ALWAYS_INLINE void refIfNotNull(T* ptr)
> {
>     if (LIKELY(ptr != nullptr))
>@@ -44,6 +59,7 @@ template<typename T> ALWAYS_INLINE void derefIfNotNull(T* ptr)
>     if (LIKELY(ptr != nullptr))
>         ptr->deref();
> }
>+#endif
> 
> template<typename T, typename PtrTraits>
> class RefPtr {
>@@ -54,25 +70,92 @@ public:
> 
>     static constexpr bool isRefPtr = true;
> 
>-    ALWAYS_INLINE constexpr RefPtr() : m_ptr(nullptr) { }
>-    ALWAYS_INLINE RefPtr(T* ptr) : m_ptr(ptr) { refIfNotNull(ptr); }
>-    ALWAYS_INLINE RefPtr(const RefPtr& o) : m_ptr(o.m_ptr) { refIfNotNull(PtrTraits::unwrap(m_ptr)); }
>-    template<typename X, typename Y> RefPtr(const RefPtr<X, Y>& o) : m_ptr(o.get()) { refIfNotNull(PtrTraits::unwrap(m_ptr)); }
>-
>-    ALWAYS_INLINE RefPtr(RefPtr&& o) : m_ptr(o.leakRef()) { }
>-    template<typename X, typename Y> RefPtr(RefPtr<X, Y>&& o) : m_ptr(o.leakRef()) { }
>+    ALWAYS_INLINE constexpr RefPtr()
>+        : m_ptr(nullptr)
>+        , m_token(0)
>+    { }
>+
>+    ALWAYS_INLINE RefPtr(T* ptr)
>+        : m_ptr(ptr)
>+    {
>+#if ALLOW_REF_TRACING
>+        m_token =
>+#endif
>+        refIfNotNull(ptr);
>+    }
>+
>+    ALWAYS_INLINE RefPtr(const RefPtr& o)
>+        : m_ptr(o.m_ptr)
>+    {
>+#if ALLOW_REF_TRACING
>+        m_token =
>+#endif
>+        refIfNotNull(PtrTraits::unwrap(m_ptr));
>+    }
>+
>+    template<typename X, typename Y> RefPtr(const RefPtr<X, Y>& o)
>+        : m_ptr(o.get())
>+    {
>+#if ALLOW_REF_TRACING
>+        m_token =
>+#endif
>+        refIfNotNull(PtrTraits::unwrap(m_ptr));
>+    }
>+
>+    ALWAYS_INLINE RefPtr(RefPtr&& o)
>+        : m_ptr(o.leakRef())
>+#if ALLOW_REF_TRACING
>+        , m_token(o.token())
>+#endif
>+    {
>+    }
>+
>+    template<typename X, typename Y> RefPtr(RefPtr<X, Y>&& o)
>+        : m_ptr(o.leakRef())
>+#if ALLOW_REF_TRACING
>+        , m_token(o.token())
>+#endif
>+    {
>+    }
>+    
>     template<typename X, typename Y> RefPtr(Ref<X, Y>&&);
> 
>     // Hash table deleted values, which are only constructed and never copied or destroyed.
>     RefPtr(HashTableDeletedValueType) : m_ptr(hashTableDeletedValue()) { }
>     bool isHashTableDeletedValue() const { return m_ptr == hashTableDeletedValue(); }
> 
>-    ALWAYS_INLINE ~RefPtr() { derefIfNotNull(PtrTraits::exchange(m_ptr, nullptr)); }
>+    ALWAYS_INLINE ~RefPtr()
>+    {
>+        derefIfNotNull(PtrTraits::exchange(m_ptr, nullptr)
>+#if ALLOW_REF_TRACING
>+            , m_token
>+#endif
>+        );
>+    }
> 
>     T* get() const { return PtrTraits::unwrap(m_ptr); }
> 
>-    Ref<T> releaseNonNull() { ASSERT(m_ptr); Ref<T> tmp(adoptRef(*m_ptr)); m_ptr = nullptr; return tmp; }
>-    Ref<const T> releaseConstNonNull() { ASSERT(m_ptr); Ref<const T> tmp(adoptRef(*m_ptr)); m_ptr = nullptr; return tmp; }
>+    Ref<T> releaseNonNull()
>+    {
>+        ASSERT(m_ptr);
>+        Ref<T> tmp(adoptRef(*m_ptr));
>+        m_ptr = nullptr;
>+#if ALLOW_REF_TRACING
>+        tmp.setToken(m_token);
>+#endif
>+        return tmp;
>+    }
>+
>+    Ref<const T> releaseConstNonNull()
>+    {
>+        ASSERT(m_ptr);
>+        Ref<const T> tmp(adoptRef(*m_ptr));
>+        m_ptr = nullptr;
>+#if ALLOW_REF_TRACING
>+        tmp.setToken(m_token);
>+#endif
>+        return tmp;
>+    }
> 
>     T* leakRef() WARN_UNUSED_RETURN;
> 
>@@ -102,20 +185,36 @@ public:
>     RefPtr copyRef() && = delete;
>     RefPtr copyRef() const & WARN_UNUSED_RETURN { return RefPtr(m_ptr); }
> 
>+#if ALLOW_REF_TRACING
>+    RefToken token() const { return m_token; }
>+    void setToken(RefToken token) { m_token = token; }
>+#endif
>+
> private:
>     friend RefPtr adoptRef<T, PtrTraits>(T*);
>     template<typename X, typename Y> friend class RefPtr;
> 
>     enum AdoptTag { Adopt };
>-    RefPtr(T* ptr, AdoptTag) : m_ptr(ptr) { }
>+    RefPtr(T* ptr, AdoptTag)
>+        : m_ptr(ptr)
>+#if ALLOW_REF_TRACING
>+        , m_token(0)
>+#endif
>+    { }
> 
>     typename PtrTraits::StorageType m_ptr;
>+#if ALLOW_REF_TRACING
>+    RefToken m_token;
>+#endif
> };
> 
> template<typename T, typename U>
> template<typename X, typename Y>
> inline RefPtr<T, U>::RefPtr(Ref<X, Y>&& reference)
>     : m_ptr(&reference.leakRef())
>+#if ALLOW_REF_TRACING
>+    , m_token(reference.token())
>+#endif
> {
> }
> 
>@@ -153,7 +252,11 @@ inline RefPtr<T, U>& RefPtr<T, U>::operator=(T* optr)
> template<typename T, typename U>
> inline RefPtr<T, U>& RefPtr<T, U>::operator=(std::nullptr_t)
> {
>-    derefIfNotNull(U::exchange(m_ptr, nullptr));
>+    derefIfNotNull(U::exchange(m_ptr, nullptr)
>+#if ALLOW_REF_TRACING
>+        , m_token
>+#endif
>+    );
>     return *this;
> }
> 
>@@ -185,9 +288,12 @@ inline RefPtr<T, V>& RefPtr<T, V>::operator=(Ref<U>&& reference)
> 
> template<class T, typename U>
> template<typename X, typename Y>
>-inline void RefPtr<T, U>::swap(RefPtr<X, Y>& o)
>+inline void RefPtr<T, U>::swap(RefPtr<X, Y>& other)
> {
>-    U::swap(m_ptr, o.m_ptr);
>+    U::swap(m_ptr, other.m_ptr);
>+#if ALLOW_REF_TRACING
>+    std::swap(m_token, other.m_token);
>+#endif
> }
> 
> template<typename T, typename U, typename X, typename Y, typename = std::enable_if_t<!std::is_same<U, DumbPtrTraits<T>>::value || !std::is_same<Y, DumbPtrTraits<X>>::value>>
>diff --git a/Source/WTF/wtf/RefTracker.cpp b/Source/WTF/wtf/RefTracker.cpp
>new file mode 100644
>index 00000000000..e5d13c48717
>--- /dev/null
>+++ b/Source/WTF/wtf/RefTracker.cpp
>@@ -0,0 +1,79 @@
>+/*
>+ * Copyright (C) 2018 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
>+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
>+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
>+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
>+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
>+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
>+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
>+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
>+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
>+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
>+ */
>+
>+#include "config.h"
>+#include "RefTracker.h"
>+
>+#include "StackShot.h"
>+
>+namespace WTF {
>+
>+static RefToken nextRefToken()
>+{
>+    static RefToken token;
>+    return ++token;
>+}
>+
>+RefTracker::RefTracker()
>+{
>+}
>+
>+RefTracker::~RefTracker()
>+{
>+}
>+
>+void RefTracker::dumpRemainingReferences() const
>+{
>+    for (const auto& tokenAndStack : m_refBacktraceMap) {
>+        const auto& stackShot = *tokenAndStack.value;
>+
>+        WTFLogAlways("Backtrace for token %u\n", tokenAndStack.key);
>+        const size_t framesToSkip = 4;
>+        WTFPrintBacktrace(stackShot.array() + framesToSkip, stackShot.size() - framesToSkip);
>+        WTFLogAlways("\n");
>+    }
>+}
>+
>+RefToken RefTracker::trackRef()
>+{
>+    RefToken token = nextRefToken();
>+    const size_t maxStackSize = 512;
>+    m_refBacktraceMap.add(token, std::make_unique<StackShot>(maxStackSize));
>+    return token;
>+}
>+
>+void RefTracker::trackDeref(RefToken token)
>+{
>+    if (!token)
>+        return;
>+
>+    bool removed = m_refBacktraceMap.remove(token);
>+    if (!removed)
>+        WTFLogAlways("RefTracker::deref() passed token %u that was not tracked or already removed", token);
>+}
>+
>+
>+} // namespace WTF
>+
>diff --git a/Source/WTF/wtf/RefTracker.h b/Source/WTF/wtf/RefTracker.h
>new file mode 100644
>index 00000000000..e0663ab73f7
>--- /dev/null
>+++ b/Source/WTF/wtf/RefTracker.h
>@@ -0,0 +1,56 @@
>+/*
>+ * Copyright (C) 2018 Apple Inc. All rights reserved.
>+ *
>+ * Redistribution and use in source and binary forms, with or without
>+ * modification, are permitted provided that the following conditions
>+ * are met:
>+ * 1. Redistributions of source code must retain the above copyright
>+ *    notice, this list of conditions and the following disclaimer.
>+ * 2. Redistributions in binary form must reproduce the above copyright
>+ *    notice, this list of conditions and the following disclaimer in the
>+ *    documentation and/or other materials provided with the distribution.
>+ *
>+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
>+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
>+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
>+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
>+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
>+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
>+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
>+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
>+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
>+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
>+ * THE POSSIBILITY OF SUCH DAMAGE.
>+ */
>+
>+#pragma once
>+
>+#include <wtf/HashMap.h>
>+#include <wtf/Ref.h>
>+
>+#if ALLOW_REF_TRACING
>+
>+namespace WTF {
>+
>+class StackShot;
>+
>+class RefTracker
>+{
>+public:
>+    WTF_EXPORT_PRIVATE RefTracker();
>+    WTF_EXPORT_PRIVATE ~RefTracker();
>+
>+    WTF_EXPORT_PRIVATE RefToken trackRef();
>+    WTF_EXPORT_PRIVATE void trackDeref(RefToken);
>+
>+    WTF_EXPORT_PRIVATE void dumpRemainingReferences() const;
>+
>+private:
>+    HashMap<RefToken, std::unique_ptr<StackShot>> m_refBacktraceMap;
>+};
>+
>+} // namespace WTF
>+
>+using WTF::RefTracker;
>+
>+#endif // ALLOW_REF_TRACING
>diff --git a/Source/WTF/wtf/SizeLimits.cpp b/Source/WTF/wtf/SizeLimits.cpp
>index b0ad14044f3..b7bc622d21b 100644
>--- a/Source/WTF/wtf/SizeLimits.cpp
>+++ b/Source/WTF/wtf/SizeLimits.cpp
>@@ -54,8 +54,10 @@ struct SameSizeAsRefCounted {
> };
> #endif
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(RefCounted<int>) == sizeof(SameSizeAsRefCounted), "RefCounted should stay small!");
> static_assert(sizeof(RefPtr<RefCounted<int>>) == sizeof(int*), "RefPtr should stay small!");
>+#endif
> 
> #if !ASAN_ENABLED
> template<typename T, unsigned inlineCapacity = 0>
>diff --git a/Source/WTF/wtf/ThreadSafeRefCounted.h b/Source/WTF/wtf/ThreadSafeRefCounted.h
>index c4e809ae93a..20b172661a4 100644
>--- a/Source/WTF/wtf/ThreadSafeRefCounted.h
>+++ b/Source/WTF/wtf/ThreadSafeRefCounted.h
>@@ -29,6 +29,7 @@
> #include <wtf/FastMalloc.h>
> #include <wtf/MainThread.h>
> #include <wtf/Noncopyable.h>
>+#include <wtf/Ref.h>
> 
> namespace WTF {
> 
>@@ -38,9 +39,10 @@ class ThreadSafeRefCountedBase {
> public:
>     ThreadSafeRefCountedBase() = default;
> 
>-    void ref() const
>+    REF_RETURN_TYPE ref() const
>     {
>         ++m_refCount;
>+        DEFAULT_REF_RETURN;
>     }
> 
>     bool hasOneRef() const
>@@ -55,7 +57,7 @@ public:
> 
> protected:
>     // Returns whether the pointer should be freed or not.
>-    bool derefBase() const
>+    bool derefBase(DEREF_ARGUMENT_TYPE) const
>     {
>         return !--m_refCount;
>     }
>@@ -68,9 +70,9 @@ enum class DestructionThread { Any, Main };
> 
> template<class T, DestructionThread destructionThread = DestructionThread::Any> class ThreadSafeRefCounted : public ThreadSafeRefCountedBase {
> public:
>-    void deref() const
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) const
>     {
>-        if (!derefBase())
>+        if (!derefBase(DEREF_ARGUMENT_NAME))
>             return;
>         if (destructionThread == DestructionThread::Any || isMainThread()) {
>             delete static_cast<const T*>(this);
>diff --git a/Source/WTF/wtf/ThreadingPthreads.cpp b/Source/WTF/wtf/ThreadingPthreads.cpp
>index a3f428c8c98..c49e655e905 100644
>--- a/Source/WTF/wtf/ThreadingPthreads.cpp
>+++ b/Source/WTF/wtf/ThreadingPthreads.cpp
>@@ -475,7 +475,7 @@ void Thread::destructTLS(void* data)
> 
>     if (thread->m_isDestroyedOnce) {
>         thread->didExit();
>-        thread->deref();
>+        thread->deref(DEREF_DEFAULT_ARGUMENTS);
>         return;
>     }
> 
>diff --git a/Source/WTF/wtf/WTFAssertions.cpp b/Source/WTF/wtf/WTFAssertions.cpp
>index 9870764cf02..a1b73f8a6f6 100644
>--- a/Source/WTF/wtf/WTFAssertions.cpp
>+++ b/Source/WTF/wtf/WTFAssertions.cpp
>@@ -41,11 +41,13 @@ uintptr_t dummyPoison = 0;
> static_assert(sizeof(Bag<DummyStruct>) == sizeof(void*), "");
> static_assert(sizeof(PoisonedBag<Poison<dummyPoison>, DummyStruct>) == sizeof(void*), "");
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(Ref<DummyStruct>) == sizeof(DummyStruct*), "");
> static_assert(sizeof(PoisonedRef<Poison<dummyPoison>, DummyStruct>) == sizeof(DummyStruct*), "");
> 
> static_assert(sizeof(RefPtr<DummyStruct>) == sizeof(DummyStruct*), "");
> static_assert(sizeof(PoisonedRefPtr<Poison<dummyPoison>, DummyStruct>) == sizeof(DummyStruct*), "");
>+#endif
> 
> static_assert(sizeof(PoisonedUniquePtr<Poison<dummyPoison>, DummyStruct>) == sizeof(DummyStruct*), "");
> static_assert(sizeof(PoisonedUniquePtr<Poison<dummyPoison>, int[]>) == sizeof(int*), "");
>diff --git a/Source/WTF/wtf/text/StringImpl.h b/Source/WTF/wtf/text/StringImpl.h
>index 2aa0c918753..e060969997d 100644
>--- a/Source/WTF/wtf/text/StringImpl.h
>+++ b/Source/WTF/wtf/text/StringImpl.h
>@@ -320,8 +320,8 @@ public:
>     bool hasOneRef() const { return m_refCount == s_refCountIncrement; }
>     bool hasAtLeastOneRef() const { return m_refCount; } // For assertions.
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     class StaticStringImpl : private StringImplShape {
>         WTF_MAKE_NONCOPYABLE(StaticStringImpl);
>@@ -1034,14 +1034,15 @@ inline void StringImpl::setHash(unsigned hash) const
>     m_hashAndFlags |= hash; // Store hash with flags in low bits.
> }
> 
>-inline void StringImpl::ref()
>+inline REF_RETURN_TYPE StringImpl::ref()
> {
>     STRING_STATS_REF_STRING(*this);
> 
>     m_refCount += s_refCountIncrement;
>+    DEFAULT_REF_RETURN;
> }
> 
>-inline void StringImpl::deref()
>+inline void StringImpl::deref(DEREF_ARGUMENT_TYPE)
> {
>     STRING_STATS_DEREF_STRING(*this);
> 
>diff --git a/Source/WTF/wtf/text/WTFString.h b/Source/WTF/wtf/text/WTFString.h
>index 17e2c69eb99..33ca3ab037e 100644
>--- a/Source/WTF/wtf/text/WTFString.h
>+++ b/Source/WTF/wtf/text/WTFString.h
>@@ -374,7 +374,9 @@ private:
>     RefPtr<StringImpl> m_impl;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(String) == sizeof(void*), "String should effectively be a pointer to a StringImpl, and efficient to pass by value");
>+#endif
> 
> inline bool operator==(const String& a, const String& b) { return equal(a.impl(), b.impl()); }
> inline bool operator==(const String& a, const LChar* b) { return equal(a.impl(), b); }
>diff --git a/Source/WebCore/Modules/applepay/ApplePaySession.h b/Source/WebCore/Modules/applepay/ApplePaySession.h
>index 70612760b11..21c0adc290f 100644
>--- a/Source/WebCore/Modules/applepay/ApplePaySession.h
>+++ b/Source/WebCore/Modules/applepay/ApplePaySession.h
>@@ -107,8 +107,8 @@ private:
>     // EventTargetWithInlineData.
>     EventTargetInterface eventTargetInterface() const override { return ApplePaySessionEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const override { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     // PaymentSession
>     unsigned version() const override;
>diff --git a/Source/WebCore/Modules/encryptedmedia/MediaKeySession.h b/Source/WebCore/Modules/encryptedmedia/MediaKeySession.h
>index ecc57b450cd..7263e69e365 100644
>--- a/Source/WebCore/Modules/encryptedmedia/MediaKeySession.h
>+++ b/Source/WebCore/Modules/encryptedmedia/MediaKeySession.h
>@@ -90,8 +90,8 @@ private:
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const override { return MediaKeySessionEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const override { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     // ActiveDOMObject
>     bool hasPendingActivity() const override;
>diff --git a/Source/WebCore/Modules/encryptedmedia/legacy/WebKitMediaKeySession.h b/Source/WebCore/Modules/encryptedmedia/legacy/WebKitMediaKeySession.h
>index 1a22d32f5a6..fdae0a60ee0 100644
>--- a/Source/WebCore/Modules/encryptedmedia/legacy/WebKitMediaKeySession.h
>+++ b/Source/WebCore/Modules/encryptedmedia/legacy/WebKitMediaKeySession.h
>@@ -73,8 +73,8 @@ private:
>     void sendError(MediaKeyErrorCode, uint32_t systemCode) final;
>     String mediaKeysStorageDirectory() const final;
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void stop() final;
>     bool canSuspendForDocumentSuspension() const final;
>diff --git a/Source/WebCore/Modules/indexeddb/IDBDatabase.h b/Source/WebCore/Modules/indexeddb/IDBDatabase.h
>index 76a12859101..a27f501a418 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBDatabase.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBDatabase.h
>@@ -74,8 +74,8 @@ public:
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const final { return IDBDatabaseEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ThreadSafeRefCounted<IDBDatabase>::ref(); }
>-    void derefEventTarget() final { ThreadSafeRefCounted<IDBDatabase>::deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ThreadSafeRefCounted<IDBDatabase>::ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { ThreadSafeRefCounted<IDBDatabase>::deref(DEREF_ARGUMENT_NAME); }
> 
>     using ThreadSafeRefCounted<IDBDatabase>::ref;
>     using ThreadSafeRefCounted<IDBDatabase>::deref;
>diff --git a/Source/WebCore/Modules/indexeddb/IDBIndex.cpp b/Source/WebCore/Modules/indexeddb/IDBIndex.cpp
>index 308305b8e6e..64e5f096aff 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBIndex.cpp
>+++ b/Source/WebCore/Modules/indexeddb/IDBIndex.cpp
>@@ -365,14 +365,15 @@ void IDBIndex::markAsDeleted()
>     m_deleted = true;
> }
> 
>-void IDBIndex::ref()
>+REF_RETURN_TYPE IDBIndex::ref()
> {
>     m_objectStore.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void IDBIndex::deref()
>+void IDBIndex::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_objectStore.deref();
>+    m_objectStore.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/Modules/indexeddb/IDBIndex.h b/Source/WebCore/Modules/indexeddb/IDBIndex.h
>index b3134fde231..ca3e13b8b6e 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBIndex.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBIndex.h
>@@ -79,8 +79,8 @@ public:
>     void markAsDeleted();
>     bool isDeleted() const { return m_deleted; }
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     void* objectStoreAsOpaqueRoot() { return &m_objectStore; }
> 
>diff --git a/Source/WebCore/Modules/indexeddb/IDBObjectStore.cpp b/Source/WebCore/Modules/indexeddb/IDBObjectStore.cpp
>index 12c9bad51a3..5bd107c2d31 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBObjectStore.cpp
>+++ b/Source/WebCore/Modules/indexeddb/IDBObjectStore.cpp
>@@ -688,14 +688,15 @@ void IDBObjectStore::renameReferencedIndex(IDBIndex& index, const String& newNam
>     m_referencedIndexes.set(newName, m_referencedIndexes.take(index.info().name()));
> }
> 
>-void IDBObjectStore::ref()
>+REF_RETURN_TYPE IDBObjectStore::ref()
> {
>     m_transaction.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void IDBObjectStore::deref()
>+void IDBObjectStore::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_transaction.deref();
>+    m_transaction.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/Modules/indexeddb/IDBObjectStore.h b/Source/WebCore/Modules/indexeddb/IDBObjectStore.h
>index ea8fd5ca32c..de683b555e3 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBObjectStore.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBObjectStore.h
>@@ -103,8 +103,8 @@ public:
> 
>     void rollbackForVersionChangeAbort();
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     void visitReferencedIndexes(JSC::SlotVisitor&) const;
>     void renameReferencedIndex(IDBIndex&, const String& newName);
>diff --git a/Source/WebCore/Modules/indexeddb/IDBRequest.h b/Source/WebCore/Modules/indexeddb/IDBRequest.h
>index e914344fe8d..6e1c1e6ed1e 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBRequest.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBRequest.h
>@@ -150,8 +150,8 @@ private:
>     void stop() final;
>     virtual void cancelForStop();
> 
>-    void refEventTarget() final { RefCounted::ref(); }
>-    void derefEventTarget() final { RefCounted::deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return RefCounted::ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { RefCounted::deref(DEREF_ARGUMENT_NAME); }
>     void uncaughtExceptionInEventHandler() final;
> 
>     virtual bool isOpenDBRequest() const { return false; }
>diff --git a/Source/WebCore/Modules/indexeddb/IDBTransaction.h b/Source/WebCore/Modules/indexeddb/IDBTransaction.h
>index ecac146e5d6..cb3034efc8c 100644
>--- a/Source/WebCore/Modules/indexeddb/IDBTransaction.h
>+++ b/Source/WebCore/Modules/indexeddb/IDBTransaction.h
>@@ -82,8 +82,10 @@ public:
> 
>     EventTargetInterface eventTargetInterface() const final { return IDBTransactionEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ThreadSafeRefCounted::ref(); }
>-    void derefEventTarget() final { ThreadSafeRefCounted::deref(); }
>+
>+    REF_RETURN_TYPE refEventTarget() final { return ThreadSafeRefCounted::ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { ThreadSafeRefCounted::deref(DEREF_ARGUMENT_NAME); }
>+
>     using EventTarget::dispatchEvent;
>     void dispatchEvent(Event&) final;
> 
>diff --git a/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.cpp b/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.cpp
>index 15ac07e4644..bd8f9606cef 100644
>--- a/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.cpp
>+++ b/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.cpp
>@@ -50,14 +50,15 @@ IDBConnectionProxy::IDBConnectionProxy(IDBConnectionToServer& connection)
>     ASSERT(isMainThread());
> }
> 
>-void IDBConnectionProxy::ref()
>+REF_RETURN_TYPE IDBConnectionProxy::ref()
> {
>     m_connectionToServer.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void IDBConnectionProxy::deref()
>+void IDBConnectionProxy::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_connectionToServer.deref();
>+    m_connectionToServer.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> Ref<IDBOpenDBRequest> IDBConnectionProxy::openDatabase(ScriptExecutionContext& context, const IDBDatabaseIdentifier& databaseIdentifier, uint64_t version)
>diff --git a/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.h b/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.h
>index b7728c0d52f..19dfdce46a6 100644
>--- a/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.h
>+++ b/Source/WebCore/Modules/indexeddb/client/IDBConnectionProxy.h
>@@ -111,8 +111,8 @@ public:
> 
>     uint64_t serverConnectionIdentifier() const { return m_serverConnectionIdentifier; }
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     void getAllDatabaseNames(const SecurityOrigin& mainFrameOrigin, const SecurityOrigin& openingOrigin, WTF::Function<void (const Vector<String>&)>&&);
> 
>diff --git a/Source/WebCore/Modules/indexeddb/client/IDBConnectionToServerDelegate.h b/Source/WebCore/Modules/indexeddb/client/IDBConnectionToServerDelegate.h
>index f217926ae06..f6ca96fcfcd 100644
>--- a/Source/WebCore/Modules/indexeddb/client/IDBConnectionToServerDelegate.h
>+++ b/Source/WebCore/Modules/indexeddb/client/IDBConnectionToServerDelegate.h
>@@ -88,8 +88,8 @@ public:
> 
>     virtual void getAllDatabaseNames(const SecurityOriginData& mainFrameOrigin, const SecurityOriginData& openingOrigin, uint64_t callbackID) = 0;
> 
>-    virtual void ref() = 0;
>-    virtual void deref() = 0;
>+    virtual REF_RETURN_TYPE ref() = 0;
>+    virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> };
> 
> } // namespace IDBClient
>diff --git a/Source/WebCore/Modules/indexeddb/server/IDBConnectionToClientDelegate.h b/Source/WebCore/Modules/indexeddb/server/IDBConnectionToClientDelegate.h
>index 479742a9da9..593a15688e3 100644
>--- a/Source/WebCore/Modules/indexeddb/server/IDBConnectionToClientDelegate.h
>+++ b/Source/WebCore/Modules/indexeddb/server/IDBConnectionToClientDelegate.h
>@@ -72,8 +72,8 @@ public:
> 
>     virtual void didGetAllDatabaseNames(uint64_t callbackID, const Vector<String>& databaseNames) = 0;
> 
>-    virtual void ref() = 0;
>-    virtual void deref() = 0;
>+    virtual REF_RETURN_TYPE ref() = 0;
>+    virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> };
> 
> } // namespace IDBServer
>diff --git a/Source/WebCore/Modules/indexeddb/shared/InProcessIDBServer.h b/Source/WebCore/Modules/indexeddb/shared/InProcessIDBServer.h
>index 473ea5b172a..cc02f0ed601 100644
>--- a/Source/WebCore/Modules/indexeddb/shared/InProcessIDBServer.h
>+++ b/Source/WebCore/Modules/indexeddb/shared/InProcessIDBServer.h
>@@ -109,8 +109,8 @@ public:
>     void notifyOpenDBRequestBlocked(const IDBResourceIdentifier& requestIdentifier, uint64_t oldVersion, uint64_t newVersion) final;
>     void didGetAllDatabaseNames(uint64_t callbackID, const Vector<String>& databaseNames) final;
> 
>-    void ref() override { RefCounted<InProcessIDBServer>::ref(); }
>-    void deref() override { RefCounted<InProcessIDBServer>::deref(); }
>+    REF_RETURN_TYPE ref() override { return RefCounted<InProcessIDBServer>::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { RefCounted<InProcessIDBServer>::deref(DEREF_ARGUMENT_NAME); }
> 
>     void prepareForAccessToTemporaryFile(const String&) override { }
>     void accessToTemporaryFileComplete(const String& path) override;
>diff --git a/Source/WebCore/Modules/mediasession/MediaRemoteControls.h b/Source/WebCore/Modules/mediasession/MediaRemoteControls.h
>index cf24dea09e4..5f1f6d8281e 100644
>--- a/Source/WebCore/Modules/mediasession/MediaRemoteControls.h
>+++ b/Source/WebCore/Modules/mediasession/MediaRemoteControls.h
>@@ -67,8 +67,8 @@ private:
> 
>     MediaSession* m_session { nullptr };
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> };
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/Modules/mediasource/MediaSource.h b/Source/WebCore/Modules/mediasource/MediaSource.h
>index 29346572e30..67b0582ef7f 100644
>--- a/Source/WebCore/Modules/mediasource/MediaSource.h
>+++ b/Source/WebCore/Modules/mediasource/MediaSource.h
>@@ -114,8 +114,8 @@ private:
>     void setPrivateAndOpen(Ref<MediaSourcePrivate>&&) final;
>     void seekToTime(const MediaTime&) final;
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     EventTargetInterface eventTargetInterface() const final;
> 
>     URLRegistry& registry() const final;
>diff --git a/Source/WebCore/Modules/mediasource/SourceBuffer.h b/Source/WebCore/Modules/mediasource/SourceBuffer.h
>index c1a3dc5b08b..2d7cfa6f35e 100644
>--- a/Source/WebCore/Modules/mediasource/SourceBuffer.h
>+++ b/Source/WebCore/Modules/mediasource/SourceBuffer.h
>@@ -120,8 +120,8 @@ public:
> private:
>     SourceBuffer(Ref<SourceBufferPrivate>&&, MediaSource*);
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void stop() final;
>     const char* activeDOMObjectName() const final;
>diff --git a/Source/WebCore/Modules/mediasource/SourceBufferList.h b/Source/WebCore/Modules/mediasource/SourceBufferList.h
>index 4186b4fecb3..70d0970f526 100644
>--- a/Source/WebCore/Modules/mediasource/SourceBufferList.h
>+++ b/Source/WebCore/Modules/mediasource/SourceBufferList.h
>@@ -74,8 +74,8 @@ private:
> 
>     void scheduleEvent(const AtomicString&);
> 
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     GenericEventQueue m_asyncEventQueue;
> 
>diff --git a/Source/WebCore/Modules/mediastream/MediaDevices.h b/Source/WebCore/Modules/mediastream/MediaDevices.h
>index 04cc6059ba3..013eff8e61b 100644
>--- a/Source/WebCore/Modules/mediastream/MediaDevices.h
>+++ b/Source/WebCore/Modules/mediastream/MediaDevices.h
>@@ -87,8 +87,8 @@ private:
>     // EventTargetWithInlineData.
>     EventTargetInterface eventTargetInterface() const override { return MediaDevicesEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return m_scriptExecutionContext; }
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     WeakPtr<MediaDevices> createWeakPtr() { return m_weakPtrFactory.createWeakPtr(*this); }
> 
>diff --git a/Source/WebCore/Modules/mediastream/MediaStream.h b/Source/WebCore/Modules/mediastream/MediaStream.h
>index 1c1ae11b80e..9f27439822f 100644
>--- a/Source/WebCore/Modules/mediastream/MediaStream.h
>+++ b/Source/WebCore/Modules/mediastream/MediaStream.h
>@@ -122,8 +122,8 @@ protected:
> private:
> 
>     // EventTarget
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // MediaStreamTrack::Observer
>     void trackDidEnd() final;
>diff --git a/Source/WebCore/Modules/mediastream/MediaStreamTrack.h b/Source/WebCore/Modules/mediastream/MediaStreamTrack.h
>index da1b1c0607b..273d7d9ae42 100644
>--- a/Source/WebCore/Modules/mediastream/MediaStreamTrack.h
>+++ b/Source/WebCore/Modules/mediastream/MediaStreamTrack.h
>@@ -158,8 +158,8 @@ private:
>     bool canSuspendForDocumentSuspension() const final;
> 
>     // EventTarget
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     EventTargetInterface eventTargetInterface() const final { return MediaStreamTrackEventTargetInterfaceType; }
> 
>     // MediaStreamTrackPrivate::Observer
>diff --git a/Source/WebCore/Modules/mediastream/RTCDTMFSender.h b/Source/WebCore/Modules/mediastream/RTCDTMFSender.h
>index 00fce07c952..da6521c33bc 100644
>--- a/Source/WebCore/Modules/mediastream/RTCDTMFSender.h
>+++ b/Source/WebCore/Modules/mediastream/RTCDTMFSender.h
>@@ -62,8 +62,8 @@ private:
>     EventTargetInterface eventTargetInterface() const final { return RTCDTMFSenderEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void didPlayTone(const String&);
> 
>diff --git a/Source/WebCore/Modules/mediastream/RTCDataChannel.h b/Source/WebCore/Modules/mediastream/RTCDataChannel.h
>index 620adb4348c..46ddb548b93 100644
>--- a/Source/WebCore/Modules/mediastream/RTCDataChannel.h
>+++ b/Source/WebCore/Modules/mediastream/RTCDataChannel.h
>@@ -85,8 +85,8 @@ private:
>     EventTargetInterface eventTargetInterface() const final { return RTCDataChannelEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return m_scriptExecutionContext; }
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     ExceptionOr<void> sendRawData(const char* data, size_t length);
> 
>diff --git a/Source/WebCore/Modules/mediastream/RTCPeerConnection.h b/Source/WebCore/Modules/mediastream/RTCPeerConnection.h
>index e99751d6ba1..fe393550bf9 100644
>--- a/Source/WebCore/Modules/mediastream/RTCPeerConnection.h
>+++ b/Source/WebCore/Modules/mediastream/RTCPeerConnection.h
>@@ -180,8 +180,8 @@ private:
>     void applyRotationForOutgoingVideoSources() { m_backend->applyRotationForOutgoingVideoSources(); }
> 
>     // EventTarget implementation.
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     void dispatchEvent(Event&) final;
> 
>     // ActiveDOMObject
>diff --git a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.h b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.h
>index 22ae284e852..4251c92d651 100644
>--- a/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.h
>+++ b/Source/WebCore/Modules/mediastream/libwebrtc/LibWebRTCMediaEndpoint.h
>@@ -129,7 +129,7 @@ private:
>     void AddRef() const { ref(); }
>     rtc::RefCountReleaseStatus Release() const
>     {
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>         return refCount() ? rtc::RefCountReleaseStatus::kDroppedLastRef : rtc::RefCountReleaseStatus::kOtherRefsRemained;
>     }
> 
>diff --git a/Source/WebCore/Modules/notifications/Notification.h b/Source/WebCore/Modules/notifications/Notification.h
>index 6c44eabb86a..287d1c025f6 100644
>--- a/Source/WebCore/Modules/notifications/Notification.h
>+++ b/Source/WebCore/Modules/notifications/Notification.h
>@@ -100,8 +100,8 @@ private:
>     bool canSuspendForDocumentSuspension() const final;
>     void stop() final;
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     String m_title;
>     Direction m_direction;
>diff --git a/Source/WebCore/Modules/paymentrequest/PaymentRequest.h b/Source/WebCore/Modules/paymentrequest/PaymentRequest.h
>index 7457ad7382d..f8d28030fba 100644
>--- a/Source/WebCore/Modules/paymentrequest/PaymentRequest.h
>+++ b/Source/WebCore/Modules/paymentrequest/PaymentRequest.h
>@@ -118,8 +118,8 @@ private:
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const final { return PaymentRequestEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     PaymentOptions m_options;
>     PaymentDetailsInit m_details;
>diff --git a/Source/WebCore/Modules/speech/SpeechSynthesisUtterance.h b/Source/WebCore/Modules/speech/SpeechSynthesisUtterance.h
>index 8c24f77d379..68cedf4006b 100644
>--- a/Source/WebCore/Modules/speech/SpeechSynthesisUtterance.h
>+++ b/Source/WebCore/Modules/speech/SpeechSynthesisUtterance.h
>@@ -72,8 +72,8 @@ private:
> 
>     ScriptExecutionContext* scriptExecutionContext() const final { return ContextDestructionObserver::scriptExecutionContext(); }
>     EventTargetInterface eventTargetInterface() const final { return SpeechSynthesisUtteranceEventTargetInterfaceType; }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     RefPtr<PlatformSpeechSynthesisUtterance> m_platformUtterance;
>     RefPtr<SpeechSynthesisVoice> m_voice;
>diff --git a/Source/WebCore/Modules/webaudio/AudioBufferSourceNode.cpp b/Source/WebCore/Modules/webaudio/AudioBufferSourceNode.cpp
>index 5e62c5ac2dc..4f7be23f004 100644
>--- a/Source/WebCore/Modules/webaudio/AudioBufferSourceNode.cpp
>+++ b/Source/WebCore/Modules/webaudio/AudioBufferSourceNode.cpp
>@@ -556,9 +556,9 @@ void AudioBufferSourceNode::setPannerNode(PannerNode* pannerNode)
> {
>     if (m_pannerNode != pannerNode && !hasFinished()) {
>         if (pannerNode)
>-            pannerNode->ref(AudioNode::RefTypeConnection);
>+            pannerNode->refConnection();
>         if (m_pannerNode)
>-            m_pannerNode->deref(AudioNode::RefTypeConnection);
>+            m_pannerNode->derefConnection();
> 
>         m_pannerNode = pannerNode;
>     }
>@@ -567,7 +567,7 @@ void AudioBufferSourceNode::setPannerNode(PannerNode* pannerNode)
> void AudioBufferSourceNode::clearPannerNode()
> {
>     if (m_pannerNode) {
>-        m_pannerNode->deref(AudioNode::RefTypeConnection);
>+        m_pannerNode->derefConnection();
>         m_pannerNode = nullptr;
>     }
> }
>diff --git a/Source/WebCore/Modules/webaudio/AudioContext.cpp b/Source/WebCore/Modules/webaudio/AudioContext.cpp
>index 1ab8bf25f34..c00b990d490 100644
>--- a/Source/WebCore/Modules/webaudio/AudioContext.cpp
>+++ b/Source/WebCore/Modules/webaudio/AudioContext.cpp
>@@ -668,7 +668,7 @@ void AudioContext::refNode(AudioNode& node)
>     ASSERT(isMainThread());
>     AutoLocker locker(*this);
>     
>-    node.ref(AudioNode::RefTypeConnection);
>+    node.refConnection();
>     m_referencedNodes.append(&node);
> }
> 
>@@ -676,7 +676,7 @@ void AudioContext::derefNode(AudioNode& node)
> {
>     ASSERT(isGraphOwner());
>     
>-    node.deref(AudioNode::RefTypeConnection);
>+    node.derefConnection();
> 
>     ASSERT(m_referencedNodes.contains(&node));
>     m_referencedNodes.removeFirst(&node);
>@@ -686,7 +686,7 @@ void AudioContext::derefUnfinishedSourceNodes()
> {
>     ASSERT(isMainThread() && isAudioThreadFinished());
>     for (auto& node : m_referencedNodes)
>-        node->deref(AudioNode::RefTypeConnection);
>+        node->derefConnection();
> 
>     m_referencedNodes.clear();
> }
>diff --git a/Source/WebCore/Modules/webaudio/AudioContext.h b/Source/WebCore/Modules/webaudio/AudioContext.h
>index 760a4e7114f..f3cf49761dc 100644
>--- a/Source/WebCore/Modules/webaudio/AudioContext.h
>+++ b/Source/WebCore/Modules/webaudio/AudioContext.h
>@@ -328,8 +328,8 @@ private:
>     void visibilityStateChanged() final;
> 
>     // EventTarget
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     void handleDirtyAudioSummingJunctions();
>     void handleDirtyAudioNodeOutputs();
>diff --git a/Source/WebCore/Modules/webaudio/AudioNode.cpp b/Source/WebCore/Modules/webaudio/AudioNode.cpp
>index f200b050e72..1e690da3b91 100644
>--- a/Source/WebCore/Modules/webaudio/AudioNode.cpp
>+++ b/Source/WebCore/Modules/webaudio/AudioNode.cpp
>@@ -389,31 +389,21 @@ void AudioNode::disableOutputsIfNecessary()
>     }
> }
> 
>-void AudioNode::ref(RefType refType)
>+void AudioNode::refConnection()
> {
>-    switch (refType) {
>-    case RefTypeNormal:
>-        ++m_normalRefCount;
>-        break;
>-    case RefTypeConnection:
>-        ++m_connectionRefCount;
>-        break;
>-    default:
>-        ASSERT_NOT_REACHED();
>-    }
>+    ++m_connectionRefCount;
> 
> #if DEBUG_AUDIONODE_REFERENCES
>-    fprintf(stderr, "%p: %d: AudioNode::ref(%d) %d %d\n", this, nodeType(), refType, m_normalRefCount, m_connectionRefCount);
>+    fprintf(stderr, "%p: %d: AudioNode::refConnection() %d %d\n", this, nodeType(), m_normalRefCount, m_connectionRefCount);
> #endif
> 
>     // See the disabling code in finishDeref() below. This handles the case where a node
>     // is being re-connected after being used at least once and disconnected.
>     // In this case, we need to re-enable.
>-    if (refType == RefTypeConnection)
>-        enableOutputsIfNecessary();
>+    enableOutputsIfNecessary();
> }
> 
>-void AudioNode::deref(RefType refType)
>+void AudioNode::derefConnection()
> {
>     // The actually work for deref happens completely within the audio context's graph lock.
>     // In the case of the audio thread, we must use a tryLock to avoid glitches.
>@@ -430,14 +420,13 @@ void AudioNode::deref(RefType refType)
>     
>     if (hasLock) {
>         // This is where the real deref work happens.
>-        finishDeref(refType);
>+        finishDeref(RefTypeConnection);
> 
>         if (mustReleaseLock)
>             context().unlock();
>     } else {
>         // We were unable to get the lock, so put this in a list to finish up later.
>         ASSERT(context().isAudioThread());
>-        ASSERT(refType == RefTypeConnection);
>         context().addDeferredFinishDeref(this);
>     }
> 
>@@ -448,6 +437,49 @@ void AudioNode::deref(RefType refType)
>         context().deleteMarkedNodes();
> }
> 
>+REF_RETURN_TYPE AudioNode::ref()
>+{
>+    ++m_normalRefCount;
>+
>+#if DEBUG_AUDIONODE_REFERENCES
>+    fprintf(stderr, "%p: %d: AudioNode::ref() %d %d\n", this, nodeType(), m_normalRefCount, m_connectionRefCount);
>+#endif
>+
>+    DEFAULT_REF_RETURN;
>+}
>+
>+void AudioNode::deref(DEREF_ARGUMENT_TYPE)
>+{
>+    // The actually work for deref happens completely within the audio context's graph lock.
>+    // In the case of the audio thread, we must use a tryLock to avoid glitches.
>+    bool hasLock = false;
>+    bool mustReleaseLock = false;
>+    
>+    if (context().isAudioThread()) {
>+        // Real-time audio thread must not contend lock (to avoid glitches).
>+        hasLock = context().tryLock(mustReleaseLock);
>+    } else {
>+        context().lock(mustReleaseLock);
>+        hasLock = true;
>+    }
>+    
>+    if (hasLock) {
>+        // This is where the real deref work happens.
>+        finishDeref(RefTypeNormal);
>+
>+        if (mustReleaseLock)
>+            context().unlock();
>+    } else {
>+        ASSERT_NOT_REACHED();
>+    }
>+
>+    // Once AudioContext::uninitialize() is called there's no more chances for deleteMarkedNodes() to get called, so we call here.
>+    // We can't call in AudioContext::~AudioContext() since it will never be called as long as any AudioNode is alive
>+    // because AudioNodes keep a reference to the context.
>+    if (context().isAudioThreadFinished())
>+        context().deleteMarkedNodes();
>+}
>+
> void AudioNode::finishDeref(RefType refType)
> {
>     ASSERT(context().isGraphOwner());
>diff --git a/Source/WebCore/Modules/webaudio/AudioNode.h b/Source/WebCore/Modules/webaudio/AudioNode.h
>index fbbc5e0f503..6fd4c37304f 100644
>--- a/Source/WebCore/Modules/webaudio/AudioNode.h
>+++ b/Source/WebCore/Modules/webaudio/AudioNode.h
>@@ -91,8 +91,11 @@ public:
>     enum RefType { RefTypeNormal, RefTypeConnection };
> 
>     // Can be called from main thread or context's audio thread.
>-    void ref(RefType refType = RefTypeNormal);
>-    void deref(RefType refType = RefTypeNormal);
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
>+
>+    void refConnection();
>+    void derefConnection();
> 
>     // Can be called from main thread or context's audio thread.  It must be called while the context's graph lock is held.
>     void finishDeref(RefType refType);
>@@ -212,8 +215,8 @@ private:
>     static int s_nodeCount[NodeTypeEnd];
> #endif
> 
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE) override { deref(); }
> 
> protected:
>     unsigned m_channelCount;
>diff --git a/Source/WebCore/Modules/webaudio/AudioNodeInput.cpp b/Source/WebCore/Modules/webaudio/AudioNodeInput.cpp
>index ccaa51d822e..2b7e2934203 100644
>--- a/Source/WebCore/Modules/webaudio/AudioNodeInput.cpp
>+++ b/Source/WebCore/Modules/webaudio/AudioNodeInput.cpp
>@@ -59,7 +59,7 @@ void AudioNodeInput::connect(AudioNodeOutput* output)
>     changedOutputs();
> 
>     // Sombody has just connected to us, so count it as a reference.
>-    node()->ref(AudioNode::RefTypeConnection);
>+    node()->refConnection();
> }
> 
> void AudioNodeInput::disconnect(AudioNodeOutput* output)
>@@ -74,14 +74,14 @@ void AudioNodeInput::disconnect(AudioNodeOutput* output)
>     if (m_outputs.remove(output)) {
>         changedOutputs();
>         output->removeInput(this);
>-        node()->deref(AudioNode::RefTypeConnection); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
>+        node()->derefConnection(); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
>         return;
>     }
>     
>     // Otherwise, try to disconnect from disabled connections.
>     if (m_disabledOutputs.remove(output)) {
>         output->removeInput(this);
>-        node()->deref(AudioNode::RefTypeConnection); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
>+        node()->derefConnection(); // Note: it's important to return immediately after all deref() calls since the node may be deleted.
>         return;
>     }
> 
>diff --git a/Source/WebCore/Modules/webaudio/MediaElementAudioSourceNode.cpp b/Source/WebCore/Modules/webaudio/MediaElementAudioSourceNode.cpp
>index 9eca86f2103..7e86ad5c64c 100644
>--- a/Source/WebCore/Modules/webaudio/MediaElementAudioSourceNode.cpp
>+++ b/Source/WebCore/Modules/webaudio/MediaElementAudioSourceNode.cpp
>@@ -161,7 +161,7 @@ void MediaElementAudioSourceNode::lock()
> void MediaElementAudioSourceNode::unlock()
> {
>     m_processMutex.unlock();
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/Modules/webaudio/OfflineAudioDestinationNode.cpp b/Source/WebCore/Modules/webaudio/OfflineAudioDestinationNode.cpp
>index e995b086587..cfded0257d5 100644
>--- a/Source/WebCore/Modules/webaudio/OfflineAudioDestinationNode.cpp
>+++ b/Source/WebCore/Modules/webaudio/OfflineAudioDestinationNode.cpp
>@@ -135,7 +135,7 @@ void OfflineAudioDestinationNode::offlineRender()
>     // Our work is done. Let the AudioContext know.
>     callOnMainThread([this] {
>         notifyComplete();
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> }
> 
>diff --git a/Source/WebCore/Modules/webaudio/ScriptProcessorNode.cpp b/Source/WebCore/Modules/webaudio/ScriptProcessorNode.cpp
>index 88ae04abbe3..4516ac65253 100644
>--- a/Source/WebCore/Modules/webaudio/ScriptProcessorNode.cpp
>+++ b/Source/WebCore/Modules/webaudio/ScriptProcessorNode.cpp
>@@ -196,7 +196,7 @@ void ScriptProcessorNode::process(size_t framesToProcess)
>                 fireProcessEvent();
> 
>                 // De-reference to match the ref() call in process().
>-                deref();
>+                deref(DEREF_DEFAULT_ARGUMENTS);
>             });
>         }
> 
>diff --git a/Source/WebCore/Modules/webdatabase/SQLCallbackWrapper.h b/Source/WebCore/Modules/webdatabase/SQLCallbackWrapper.h
>index d0d128096ba..5e266fbf988 100644
>--- a/Source/WebCore/Modules/webdatabase/SQLCallbackWrapper.h
>+++ b/Source/WebCore/Modules/webdatabase/SQLCallbackWrapper.h
>@@ -75,8 +75,8 @@ public:
>             ScriptExecutionContext::Task::CleanupTask,
>             [callback, scriptExecutionContextPtr] (ScriptExecutionContext& context) {
>                 ASSERT_UNUSED(context, &context == scriptExecutionContextPtr && context.isContextThread());
>-                callback->deref();
>-                scriptExecutionContextPtr->deref();
>+                callback->deref(DEREF_DEFAULT_ARGUMENTS);
>+                scriptExecutionContextPtr->deref(DEREF_DEFAULT_ARGUMENTS);
>             }
>         });
>     }
>diff --git a/Source/WebCore/Modules/websockets/ThreadableWebSocketChannel.h b/Source/WebCore/Modules/websockets/ThreadableWebSocketChannel.h
>index ca406af4c6f..03322cb3a41 100644
>--- a/Source/WebCore/Modules/websockets/ThreadableWebSocketChannel.h
>+++ b/Source/WebCore/Modules/websockets/ThreadableWebSocketChannel.h
>@@ -73,13 +73,13 @@ public:
>     virtual void suspend() = 0;
>     virtual void resume() = 0;
> 
>-    void ref() { refThreadableWebSocketChannel(); }
>-    void deref() { derefThreadableWebSocketChannel(); }
>+    REF_RETURN_TYPE ref() { refThreadableWebSocketChannel(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { derefThreadableWebSocketChannel(); }
> 
> protected:
>     virtual ~ThreadableWebSocketChannel() = default;
>-    virtual void refThreadableWebSocketChannel() = 0;
>-    virtual void derefThreadableWebSocketChannel() = 0;
>+    virtual REF_RETURN_TYPE refThreadableWebSocketChannel() = 0;
>+    virtual void derefThreadableWebSocketChannel(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> };
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/Modules/websockets/WebSocket.cpp b/Source/WebCore/Modules/websockets/WebSocket.cpp
>index 02477b9d0d0..7e8ee173763 100644
>--- a/Source/WebCore/Modules/websockets/WebSocket.cpp
>+++ b/Source/WebCore/Modules/websockets/WebSocket.cpp
>@@ -296,7 +296,7 @@ ExceptionOr<void> WebSocket::connect(const String& url, const Vector<String>& pr
>                 WebThreadRun(^{
>                     dispatchOrQueueErrorEvent();
>                     stop();
>-                    deref();
>+                    deref(DEREF_DEFAULT_ARGUMENTS);
>                 });
>             });
> #else
>diff --git a/Source/WebCore/Modules/websockets/WebSocket.h b/Source/WebCore/Modules/websockets/WebSocket.h
>index 90121f70d30..5b5835af162 100644
>--- a/Source/WebCore/Modules/websockets/WebSocket.h
>+++ b/Source/WebCore/Modules/websockets/WebSocket.h
>@@ -113,8 +113,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final;
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void didConnect() final;
>     void didReceiveMessage(const String& message) final;
>diff --git a/Source/WebCore/Modules/websockets/WebSocketChannel.cpp b/Source/WebCore/Modules/websockets/WebSocketChannel.cpp
>index 8147f0d4bc5..e62f9706191 100644
>--- a/Source/WebCore/Modules/websockets/WebSocketChannel.cpp
>+++ b/Source/WebCore/Modules/websockets/WebSocketChannel.cpp
>@@ -306,7 +306,7 @@ void WebSocketChannel::didCloseSocketStream(SocketStreamHandle& handle)
>         if (client)
>             client->didClose(m_unhandledBufferedAmount, m_receivedClosingHandshake ? WebSocketChannelClient::ClosingHandshakeComplete : WebSocketChannelClient::ClosingHandshakeIncomplete, m_closeEventCode, m_closeEventReason);
>     }
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void WebSocketChannel::didReceiveSocketStreamData(SocketStreamHandle& handle, const char* data, size_t length)
>@@ -392,7 +392,7 @@ void WebSocketChannel::didFinishLoading()
>     ASSERT(m_blobLoaderStatus == BlobLoaderStarted);
>     m_blobLoaderStatus = BlobLoaderFinished;
>     processOutgoingFrameQueue();
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void WebSocketChannel::didFail(int errorCode)
>@@ -403,7 +403,7 @@ void WebSocketChannel::didFail(int errorCode)
>     m_blobLoader = nullptr;
>     m_blobLoaderStatus = BlobLoaderFailed;
>     fail("Failed to load Blob: error code = " + String::number(errorCode)); // FIXME: Generate human-friendly reason message.
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> bool WebSocketChannel::appendToBuffer(const char* data, size_t len)
>diff --git a/Source/WebCore/Modules/websockets/WebSocketChannel.h b/Source/WebCore/Modules/websockets/WebSocketChannel.h
>index 1131ea611f9..125529fe5d7 100644
>--- a/Source/WebCore/Modules/websockets/WebSocketChannel.h
>+++ b/Source/WebCore/Modules/websockets/WebSocketChannel.h
>@@ -124,8 +124,8 @@ public:
>     using RefCounted<WebSocketChannel>::deref;
> 
> protected:
>-    void refThreadableWebSocketChannel() override { ref(); }
>-    void derefThreadableWebSocketChannel() override { deref(); }
>+    REF_RETURN_TYPE refThreadableWebSocketChannel() override { return ref(); }
>+    void derefThreadableWebSocketChannel(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     WEBCORE_EXPORT WebSocketChannel(Document&, WebSocketChannelClient&, SocketProvider&);
>diff --git a/Source/WebCore/Modules/websockets/WorkerThreadableWebSocketChannel.h b/Source/WebCore/Modules/websockets/WorkerThreadableWebSocketChannel.h
>index 812f8a02d30..f303df7d5e0 100644
>--- a/Source/WebCore/Modules/websockets/WorkerThreadableWebSocketChannel.h
>+++ b/Source/WebCore/Modules/websockets/WorkerThreadableWebSocketChannel.h
>@@ -109,8 +109,8 @@ public:
>     using RefCounted<WorkerThreadableWebSocketChannel>::deref;
> 
> protected:
>-    void refThreadableWebSocketChannel() override { ref(); }
>-    void derefThreadableWebSocketChannel() override { deref(); }
>+    REF_RETURN_TYPE refThreadableWebSocketChannel() override { return ref(); }
>+    void derefThreadableWebSocketChannel(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     // Bridge for Peer.  Running on the worker thread.
>diff --git a/Source/WebCore/Modules/webvr/VRDisplay.h b/Source/WebCore/Modules/webvr/VRDisplay.h
>index 4a99c96a967..d62bab2494c 100644
>--- a/Source/WebCore/Modules/webvr/VRDisplay.h
>+++ b/Source/WebCore/Modules/webvr/VRDisplay.h
>@@ -90,8 +90,8 @@ private:
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const override { return VRDisplayEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const override { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     // ActiveDOMObject
>     bool hasPendingActivity() const override;
>diff --git a/Source/WebCore/animation/WebAnimation.h b/Source/WebCore/animation/WebAnimation.h
>index 5314b7e8418..e3bea887e0d 100644
>--- a/Source/WebCore/animation/WebAnimation.h
>+++ b/Source/WebCore/animation/WebAnimation.h
>@@ -172,8 +172,8 @@ private:
> 
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const final { return WebAnimationEventTargetInterfaceType; }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
> };
> 
>diff --git a/Source/WebCore/bridge/NP_jsobject.cpp b/Source/WebCore/bridge/NP_jsobject.cpp
>index d9458c516ba..251f282a4fe 100644
>--- a/Source/WebCore/bridge/NP_jsobject.cpp
>+++ b/Source/WebCore/bridge/NP_jsobject.cpp
>@@ -131,7 +131,7 @@ static void jsDeallocate(NPObject* npObj)
>     }
> 
>     if (obj->rootObject)
>-        obj->rootObject->deref();
>+        obj->rootObject->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     free(obj);
> }
>diff --git a/Source/WebCore/bridge/objc/WebScriptObject.mm b/Source/WebCore/bridge/objc/WebScriptObject.mm
>index 0b5f8a9d9df..4d421caf8b7 100644
>--- a/Source/WebCore/bridge/objc/WebScriptObject.mm
>+++ b/Source/WebCore/bridge/objc/WebScriptObject.mm
>@@ -215,10 +215,10 @@ - (void)_setOriginRootObject:(RefPtr<RootObject>&&)originRootObject andRootObjec
>         _private->rootObject->gcUnprotect(_private->imp);
> 
>     if (_private->rootObject)
>-        _private->rootObject->deref();
>+        _private->rootObject->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     if (_private->originRootObject)
>-        _private->originRootObject->deref();
>+        _private->originRootObject->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     _private->rootObject = rootObject.leakRef();
>     _private->originRootObject = originRootObject.leakRef();
>@@ -307,10 +307,10 @@ - (void)dealloc
>         _private->rootObject->gcUnprotect(_private->imp);
> 
>     if (_private->rootObject)
>-        _private->rootObject->deref();
>+        _private->rootObject->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     if (_private->originRootObject)
>-        _private->originRootObject->deref();
>+        _private->originRootObject->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     [_private release];
> 
>diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>index 1a93e327b42..273fefdb462 100644
>--- a/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.cpp
>@@ -1680,13 +1680,14 @@ CSSComputedStyleDeclaration::~CSSComputedStyleDeclaration()
> //    WTFLogAlways("Destroying CSSComputedStyleDeclaration %p (count %d)", this, --CSSComputedStyleDeclarationCount);
> }
> 
>-void CSSComputedStyleDeclaration::ref()
>+REF_RETURN_TYPE CSSComputedStyleDeclaration::ref()
> {
>     CFRetain(m_treeTrap);
>     ++m_refCount;
>+    DEFAULT_REF_RETURN;
> }
> 
>-void CSSComputedStyleDeclaration::deref()
>+void CSSComputedStyleDeclaration::deref(DEREF_ARGUMENT_TYPE)
> {
>     CFRelease(m_treeTrap);
>     if (m_refCount == 1)
>diff --git a/Source/WebCore/css/CSSComputedStyleDeclaration.h b/Source/WebCore/css/CSSComputedStyleDeclaration.h
>index ab2965ef6a5..1cc2a914512 100644
>--- a/Source/WebCore/css/CSSComputedStyleDeclaration.h
>+++ b/Source/WebCore/css/CSSComputedStyleDeclaration.h
>@@ -109,8 +109,8 @@ public:
>     }
>     virtual ~CSSComputedStyleDeclaration();
> 
>-    WEBCORE_EXPORT void ref() final;
>-    WEBCORE_EXPORT void deref() final;
>+    WEBCORE_EXPORT REF_RETURN_TYPE ref() final;
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) final;
> 
>     String getPropertyValue(CSSPropertyID) const;
> 
>diff --git a/Source/WebCore/css/CSSDefaultStyleSheets.cpp b/Source/WebCore/css/CSSDefaultStyleSheets.cpp
>index 582b930f7c4..5521f4e4032 100644
>--- a/Source/WebCore/css/CSSDefaultStyleSheets.cpp
>+++ b/Source/WebCore/css/CSSDefaultStyleSheets.cpp
>@@ -146,7 +146,7 @@ void CSSDefaultStyleSheets::loadFullDefaultStyle()
>         ASSERT(defaultStyle);
>         ASSERT(defaultPrintStyle == defaultStyle);
>         delete defaultStyle;
>-        simpleDefaultStyleSheet->deref();
>+        simpleDefaultStyleSheet->deref(DEREF_DEFAULT_ARGUMENTS);
>         simpleDefaultStyleSheet = nullptr;
>     } else {
>         ASSERT(!defaultStyle);
>diff --git a/Source/WebCore/css/CSSFontFace.h b/Source/WebCore/css/CSSFontFace.h
>index 346a7b861a7..f3bb3048e93 100644
>--- a/Source/WebCore/css/CSSFontFace.h
>+++ b/Source/WebCore/css/CSSFontFace.h
>@@ -123,8 +123,8 @@ public:
>         virtual void fontLoaded(CSSFontFace&) { }
>         virtual void fontStateChanged(CSSFontFace&, Status /*oldState*/, Status /*newState*/) { }
>         virtual void fontPropertyChanged(CSSFontFace&, CSSValueList* /*oldFamilies*/ = nullptr) { }
>-        virtual void ref() = 0;
>-        virtual void deref() = 0;
>+        virtual REF_RETURN_TYPE ref() = 0;
>+        virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
>     };
> 
>     // Pending => Loading  => TimedOut
>diff --git a/Source/WebCore/css/CSSFontFaceSet.h b/Source/WebCore/css/CSSFontFaceSet.h
>index 337feab4b15..cb976d250f8 100644
>--- a/Source/WebCore/css/CSSFontFaceSet.h
>+++ b/Source/WebCore/css/CSSFontFaceSet.h
>@@ -78,8 +78,8 @@ public:
>     ExceptionOr<Vector<std::reference_wrapper<CSSFontFace>>> matchingFacesExcludingPreinstalledFonts(const String& font, const String& text);
> 
>     // CSSFontFace::Client needs to be able to be held in a RefPtr.
>-    void ref() final { RefCounted::ref(); }
>-    void deref() final { RefCounted::deref(); }
>+    REF_RETURN_TYPE ref() final { return RefCounted::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { RefCounted::deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     CSSFontFaceSet(CSSFontSelector*);
>diff --git a/Source/WebCore/css/CSSImageGeneratorValue.cpp b/Source/WebCore/css/CSSImageGeneratorValue.cpp
>index 7a8e19f230f..2f8042cfb02 100644
>--- a/Source/WebCore/css/CSSImageGeneratorValue.cpp
>+++ b/Source/WebCore/css/CSSImageGeneratorValue.cpp
>@@ -90,7 +90,7 @@ void CSSImageGeneratorValue::removeClient(RenderElement& renderer)
>     }
> 
>     if (m_clients.isEmpty())
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> GeneratedImage* CSSImageGeneratorValue::cachedImageForSize(FloatSize size)
>diff --git a/Source/WebCore/css/CSSPrimitiveValue.cpp b/Source/WebCore/css/CSSPrimitiveValue.cpp
>index a761276c703..c2d1b7a0c49 100644
>--- a/Source/WebCore/css/CSSPrimitiveValue.cpp
>+++ b/Source/WebCore/css/CSSPrimitiveValue.cpp
>@@ -491,36 +491,36 @@ void CSSPrimitiveValue::cleanup()
>     case CSS_ATTR:
>     case CSS_COUNTER_NAME:
>         if (m_value.string)
>-            m_value.string->deref();
>+            m_value.string->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_DIMENSION:
>     case CSS_COUNTER:
>-        m_value.counter->deref();
>+        m_value.counter->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_RECT:
>-        m_value.rect->deref();
>+        m_value.rect->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_QUAD:
>-        m_value.quad->deref();
>+        m_value.quad->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_PAIR:
>-        m_value.pair->deref();
>+        m_value.pair->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
> #if ENABLE(DASHBOARD_SUPPORT)
>     case CSS_DASHBOARD_REGION:
>         if (m_value.region)
>-            m_value.region->deref();
>+            m_value.region->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
> #endif
>     case CSS_CALC:
>-        m_value.calc->deref();
>+        m_value.calc->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_CALC_PERCENTAGE_WITH_NUMBER:
>     case CSS_CALC_PERCENTAGE_WITH_LENGTH:
>         ASSERT_NOT_REACHED();
>         break;
>     case CSS_SHAPE:
>-        m_value.shape->deref();
>+        m_value.shape->deref(DEREF_DEFAULT_ARGUMENTS);
>         break;
>     case CSS_FONT_FAMILY:
>         ASSERT(m_value.fontFamily);
>diff --git a/Source/WebCore/css/CSSProperty.cpp b/Source/WebCore/css/CSSProperty.cpp
>index 181ba5ddb48..5416e58748a 100644
>--- a/Source/WebCore/css/CSSProperty.cpp
>+++ b/Source/WebCore/css/CSSProperty.cpp
>@@ -33,7 +33,9 @@ struct SameSizeAsCSSProperty {
>     void* value;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(CSSProperty) == sizeof(SameSizeAsCSSProperty), CSSProperty_should_stay_small);
>+#endif
> 
> CSSPropertyID StylePropertyMetadata::shorthandID() const
> {
>diff --git a/Source/WebCore/css/CSSRuleList.cpp b/Source/WebCore/css/CSSRuleList.cpp
>index a0401091698..de0f7ea43fa 100644
>--- a/Source/WebCore/css/CSSRuleList.cpp
>+++ b/Source/WebCore/css/CSSRuleList.cpp
>@@ -37,7 +37,7 @@ StaticCSSRuleList::StaticCSSRuleList()
> 
> StaticCSSRuleList::~StaticCSSRuleList() = default;
> 
>-void StaticCSSRuleList::deref()
>+void StaticCSSRuleList::deref(DEREF_ARGUMENT_TYPE)
> { 
>     ASSERT(m_refCount);
>     if (!--m_refCount)
>diff --git a/Source/WebCore/css/CSSRuleList.h b/Source/WebCore/css/CSSRuleList.h
>index 35a0925feb6..f422b184cf7 100644
>--- a/Source/WebCore/css/CSSRuleList.h
>+++ b/Source/WebCore/css/CSSRuleList.h
>@@ -34,8 +34,8 @@ class CSSRuleList {
> public:
>     virtual ~CSSRuleList();
> 
>-    virtual void ref() = 0;
>-    virtual void deref() = 0;
>+    virtual REF_RETURN_TYPE ref() = 0;
>+    virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     virtual unsigned length() const = 0;
>     virtual CSSRule* item(unsigned index) const = 0;
>@@ -50,8 +50,8 @@ class StaticCSSRuleList final : public CSSRuleList {
> public:
>     static Ref<StaticCSSRuleList> create() { return adoptRef(*new StaticCSSRuleList); }
> 
>-    void ref() final { ++m_refCount; }
>-    void deref() final;
>+    REF_RETURN_TYPE ref() final { ++m_refCount; DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) final;
> 
>     Vector<RefPtr<CSSRule>>& rules() { return m_rules; }
>     
>@@ -77,8 +77,8 @@ public:
>     {
>     }
>     
>-    void ref() final { m_rule.ref(); }
>-    void deref() final { m_rule.deref(); }
>+    REF_RETURN_TYPE ref() final { m_rule.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) final { m_rule.deref(DEREF_DEFAULT_ARGUMENTS); }
> 
> private:
>     unsigned length() const final { return m_rule.length(); }
>diff --git a/Source/WebCore/css/CSSSegmentedFontFace.h b/Source/WebCore/css/CSSSegmentedFontFace.h
>index f66e7339320..5320261463a 100644
>--- a/Source/WebCore/css/CSSSegmentedFontFace.h
>+++ b/Source/WebCore/css/CSSSegmentedFontFace.h
>@@ -53,8 +53,8 @@ public:
>     Vector<Ref<CSSFontFace>, 1>& constituentFaces() { return m_fontFaces; }
> 
>     // CSSFontFace::Client needs to be able to be held in a RefPtr.
>-    void ref() final { RefCounted<CSSSegmentedFontFace>::ref(); }
>-    void deref() final { RefCounted<CSSSegmentedFontFace>::deref(); }
>+    REF_RETURN_TYPE ref() final { return RefCounted<CSSSegmentedFontFace>::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { RefCounted<CSSSegmentedFontFace>::deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     CSSSegmentedFontFace();
>diff --git a/Source/WebCore/css/CSSSelector.h b/Source/WebCore/css/CSSSelector.h
>index 03e9f16d884..4975ecfd4bb 100644
>--- a/Source/WebCore/css/CSSSelector.h
>+++ b/Source/WebCore/css/CSSSelector.h
>@@ -469,7 +469,7 @@ inline void CSSSelector::setValue(const AtomicString& value, bool matchLowerCase
>     // Need to do ref counting manually for the union.
>     if (!m_hasRareData) {
>         if (m_data.m_value)
>-            m_data.m_value->deref();
>+            m_data.m_value->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_data.m_value = value.impl();
>         m_data.m_value->ref();
>         return;
>@@ -535,19 +535,19 @@ inline CSSSelector::~CSSSelector()
>     m_destructorHasBeenCalled = true;
> #endif
>     if (m_hasRareData) {
>-        m_data.m_rareData->deref();
>+        m_data.m_rareData->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_data.m_rareData = nullptr;
>         m_hasRareData = false;
>     } else if (m_hasNameWithCase) {
>-        m_data.m_nameWithCase->deref();
>+        m_data.m_nameWithCase->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_data.m_nameWithCase = nullptr;
>         m_hasNameWithCase = false;
>     } else if (match() == Tag) {
>-        m_data.m_tagQName->deref();
>+        m_data.m_tagQName->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_data.m_tagQName = nullptr;
>         m_match = Unknown;
>     } else if (m_data.m_value) {
>-        m_data.m_value->deref();
>+        m_data.m_value->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_data.m_value = nullptr;
>     }
> }
>diff --git a/Source/WebCore/css/CSSStyleDeclaration.h b/Source/WebCore/css/CSSStyleDeclaration.h
>index b18c9ce3274..933d1d9dd91 100644
>--- a/Source/WebCore/css/CSSStyleDeclaration.h
>+++ b/Source/WebCore/css/CSSStyleDeclaration.h
>@@ -43,8 +43,8 @@ class CSSStyleDeclaration : public ScriptWrappable {
> public:
>     virtual ~CSSStyleDeclaration() = default;
> 
>-    virtual void ref() = 0;
>-    virtual void deref() = 0;
>+    virtual REF_RETURN_TYPE ref() = 0;
>+    virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     virtual StyledElement* parentElement() const { return nullptr; }
>     virtual CSSRule* parentRule() const = 0;
>diff --git a/Source/WebCore/css/CSSStyleSheet.cpp b/Source/WebCore/css/CSSStyleSheet.cpp
>index 1ecc5ba3708..ae7a2aef75d 100644
>--- a/Source/WebCore/css/CSSStyleSheet.cpp
>+++ b/Source/WebCore/css/CSSStyleSheet.cpp
>@@ -45,8 +45,8 @@ public:
>     StyleSheetCSSRuleList(CSSStyleSheet* sheet) : m_styleSheet(sheet) { }
>     
> private:
>-    void ref() final { m_styleSheet->ref(); }
>-    void deref() final { m_styleSheet->deref(); }
>+    REF_RETURN_TYPE ref() final { m_styleSheet->ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) final { m_styleSheet->deref(DEREF_DEFAULT_ARGUMENTS); }
> 
>     unsigned length() const final { return m_styleSheet->length(); }
>     CSSRule* item(unsigned index) const final { return m_styleSheet->item(index); }
>diff --git a/Source/WebCore/css/CSSValue.h b/Source/WebCore/css/CSSValue.h
>index d44b0750bfa..b3046cae25f 100644
>--- a/Source/WebCore/css/CSSValue.h
>+++ b/Source/WebCore/css/CSSValue.h
>@@ -51,9 +51,9 @@ public:
> 
>     // Override RefCounted's deref() to ensure operator delete is called on
>     // the appropriate subclass type.
>-    void deref()
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
>     {
>-        if (derefBase())
>+        if (derefBase(DEREF_ARGUMENT_NAME))
>             destroy();
>     }
> 
>diff --git a/Source/WebCore/css/DeprecatedCSSOMValue.h b/Source/WebCore/css/DeprecatedCSSOMValue.h
>index 77e2e36c692..ca33238e5d0 100644
>--- a/Source/WebCore/css/DeprecatedCSSOMValue.h
>+++ b/Source/WebCore/css/DeprecatedCSSOMValue.h
>@@ -48,9 +48,9 @@ public:
> 
>     // Override RefCounted's deref() to ensure operator delete is called on
>     // the appropriate subclass type.
>-    void deref()
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
>     {
>-        if (derefBase())
>+        if (derefBase(DEREF_ARGUMENT_NAME))
>             destroy();
>     }
> 
>diff --git a/Source/WebCore/css/FontFace.cpp b/Source/WebCore/css/FontFace.cpp
>index 581f5e8c9e5..d276533cec1 100644
>--- a/Source/WebCore/css/FontFace.cpp
>+++ b/Source/WebCore/css/FontFace.cpp
>@@ -448,14 +448,14 @@ void FontFace::fontStateChanged(CSSFontFace& face, CSSFontFace::Status, CSSFontF
>         // gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.  
>         if (!m_loadedPromise.isFulfilled())
>             m_loadedPromise.resolve(*this);
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>         return;
>     case CSSFontFace::Status::Failure:
>         // FIXME: This check should not be needed, but because FontFace's are sometimes adopted after they have already
>         // gone through a load cycle, we can sometimes come back through here and try to resolve the promise again.  
>         if (!m_loadedPromise.isFulfilled())
>             m_loadedPromise.reject(Exception { NetworkError });
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>         return;
>     case CSSFontFace::Status::Pending:
>         ASSERT_NOT_REACHED();
>diff --git a/Source/WebCore/css/FontFace.h b/Source/WebCore/css/FontFace.h
>index 3480030f598..1f6cca4b53b 100644
>--- a/Source/WebCore/css/FontFace.h
>+++ b/Source/WebCore/css/FontFace.h
>@@ -90,8 +90,8 @@ public:
> 
>     WeakPtr<FontFace> createWeakPtr();
> 
>-    void ref() final { RefCounted::ref(); }
>-    void deref() final { RefCounted::deref(); }
>+    REF_RETURN_TYPE ref() final { return RefCounted::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { RefCounted::deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     explicit FontFace(CSSFontSelector&);
>diff --git a/Source/WebCore/css/FontFaceSet.h b/Source/WebCore/css/FontFaceSet.h
>index 1c89172a8e7..fc0d58789bb 100644
>--- a/Source/WebCore/css/FontFaceSet.h
>+++ b/Source/WebCore/css/FontFaceSet.h
>@@ -105,8 +105,8 @@ private:
>     // EventTarget
>     EventTargetInterface eventTargetInterface() const final { return FontFaceSetEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // Callback for ReadyPromise.
>     FontFaceSet& readyPromiseResolve();
>diff --git a/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp b/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
>index 0e14bdf8e22..9f413b3ae28 100644
>--- a/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
>+++ b/Source/WebCore/css/PropertySetCSSStyleDeclaration.cpp
>@@ -129,14 +129,15 @@ PropertySetCSSStyleDeclaration* StyleAttributeMutationScope::s_currentDecl = nul
> bool StyleAttributeMutationScope::s_shouldNotifyInspector = false;
> bool StyleAttributeMutationScope::s_shouldDeliver = false;
> 
>-void PropertySetCSSStyleDeclaration::ref()
>+REF_RETURN_TYPE PropertySetCSSStyleDeclaration::ref()
> { 
>     m_propertySet->ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void PropertySetCSSStyleDeclaration::deref()
>+void PropertySetCSSStyleDeclaration::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_propertySet->deref(); 
>+    m_propertySet->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> unsigned PropertySetCSSStyleDeclaration::length() const
>@@ -353,15 +354,16 @@ StyleRuleCSSStyleDeclaration::StyleRuleCSSStyleDeclaration(MutableStylePropertie
> 
> StyleRuleCSSStyleDeclaration::~StyleRuleCSSStyleDeclaration()
> {
>-    m_propertySet->deref();
>+    m_propertySet->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
>-void StyleRuleCSSStyleDeclaration::ref()
>+REF_RETURN_TYPE StyleRuleCSSStyleDeclaration::ref()
> { 
>     ++m_refCount;
>+    DEFAULT_REF_RETURN;
> }
> 
>-void StyleRuleCSSStyleDeclaration::deref()
>+void StyleRuleCSSStyleDeclaration::deref(DEREF_ARGUMENT_TYPE)
> { 
>     ASSERT(m_refCount);
>     if (!--m_refCount)
>@@ -404,7 +406,7 @@ CSSParserContext StyleRuleCSSStyleDeclaration::cssParserContext() const
> 
> void StyleRuleCSSStyleDeclaration::reattach(MutableStyleProperties& propertySet)
> {
>-    m_propertySet->deref();
>+    m_propertySet->deref(DEREF_DEFAULT_ARGUMENTS);
>     m_propertySet = &propertySet;
>     m_propertySet->ref();
> }
>diff --git a/Source/WebCore/css/PropertySetCSSStyleDeclaration.h b/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
>index 7bc1f6ecad3..0c5cad611ad 100644
>--- a/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
>+++ b/Source/WebCore/css/PropertySetCSSStyleDeclaration.h
>@@ -61,8 +61,8 @@ protected:
>     std::unique_ptr<HashMap<CSSValue*, WeakPtr<DeprecatedCSSOMValue>>> m_cssomValueWrappers;
> 
> private:
>-    void ref() override;
>-    void deref() override;
>+    REF_RETURN_TYPE ref() override;
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) override;
> 
>     CSSRule* parentRule() const override { return nullptr; }
>     unsigned length() const final;
>@@ -98,8 +98,8 @@ public:
> 
>     void clearParentRule() { m_parentRule = nullptr; }
>     
>-    void ref() final;
>-    void deref() final;
>+    REF_RETURN_TYPE ref() final;
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) final;
> 
>     void reattach(MutableStyleProperties&);
> 
>diff --git a/Source/WebCore/css/RuleSet.h b/Source/WebCore/css/RuleSet.h
>index ba5dc60fe34..71dd75d28f2 100644
>--- a/Source/WebCore/css/RuleSet.h
>+++ b/Source/WebCore/css/RuleSet.h
>@@ -98,7 +98,9 @@ struct SameSizeAsRuleData {
>     unsigned d[4];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(RuleData) == sizeof(SameSizeAsRuleData), RuleData_should_stay_small);
>+#endif
> 
> class RuleSet {
>     WTF_MAKE_NONCOPYABLE(RuleSet); WTF_MAKE_FAST_ALLOCATED;
>diff --git a/Source/WebCore/css/StyleProperties.cpp b/Source/WebCore/css/StyleProperties.cpp
>index 30dbeb42b6b..f06c61b00fd 100644
>--- a/Source/WebCore/css/StyleProperties.cpp
>+++ b/Source/WebCore/css/StyleProperties.cpp
>@@ -102,7 +102,7 @@ ImmutableStyleProperties::~ImmutableStyleProperties()
> {
>     CSSValue** valueArray = const_cast<CSSValue**>(this->valueArray());
>     for (unsigned i = 0; i < m_arraySize; ++i)
>-        valueArray[i]->deref();
>+        valueArray[i]->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> MutableStyleProperties::MutableStyleProperties(const StyleProperties& other)
>diff --git a/Source/WebCore/css/StyleProperties.h b/Source/WebCore/css/StyleProperties.h
>index 2661ec11211..7c50cb7dfec 100644
>--- a/Source/WebCore/css/StyleProperties.h
>+++ b/Source/WebCore/css/StyleProperties.h
>@@ -51,7 +51,7 @@ class StylePropertiesBase : public RefCounted<StylePropertiesBase> {
> public:
>     // Override RefCounted's deref() to ensure operator delete is called on
>     // the appropriate subclass type.
>-    void deref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
>     
>     StylePropertiesType type() const { return static_cast<StylePropertiesType>(m_type); }
> 
>@@ -305,9 +305,9 @@ inline unsigned StyleProperties::propertyCount() const
>     return downcast<ImmutableStyleProperties>(*this).propertyCount();
> }
> 
>-inline void StylePropertiesBase::deref()
>+inline void StylePropertiesBase::deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    if (!derefBase())
>+    if (!derefBase(DEREF_ARGUMENT_NAME))
>         return;
> 
>     if (is<MutableStyleProperties>(*this))
>diff --git a/Source/WebCore/css/StyleRule.h b/Source/WebCore/css/StyleRule.h
>index 2c1fedd12e4..80c842d09fc 100644
>--- a/Source/WebCore/css/StyleRule.h
>+++ b/Source/WebCore/css/StyleRule.h
>@@ -77,9 +77,9 @@ public:
> 
>     Ref<StyleRuleBase> copy() const;
> 
>-    void deref()
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
>     {
>-        if (derefBase())
>+        if (derefBase(DEREF_ARGUMENT_NAME))
>             destroy();
>     }
> 
>diff --git a/Source/WebCore/dom/AbortSignal.h b/Source/WebCore/dom/AbortSignal.h
>index d3140acc2d8..56c45e930f4 100644
>--- a/Source/WebCore/dom/AbortSignal.h
>+++ b/Source/WebCore/dom/AbortSignal.h
>@@ -50,8 +50,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final { return AbortSignalEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ContextDestructionObserver::scriptExecutionContext(); }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     
>     bool m_aborted { false };
> };
>diff --git a/Source/WebCore/dom/ActiveDOMObject.h b/Source/WebCore/dom/ActiveDOMObject.h
>index 6156bd1703e..13600916ac7 100644
>--- a/Source/WebCore/dom/ActiveDOMObject.h
>+++ b/Source/WebCore/dom/ActiveDOMObject.h
>@@ -82,7 +82,7 @@ public:
>     {
>         ASSERT(m_pendingActivityCount > 0);
>         --m_pendingActivityCount;
>-        thisObject->deref();
>+        thisObject->deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     template<class T>
>diff --git a/Source/WebCore/dom/DOMImplementation.h b/Source/WebCore/dom/DOMImplementation.h
>index a40a2f6912f..c43b22d92ef 100644
>--- a/Source/WebCore/dom/DOMImplementation.h
>+++ b/Source/WebCore/dom/DOMImplementation.h
>@@ -33,8 +33,8 @@ class DOMImplementation : public ScriptWrappable {
> public:
>     explicit DOMImplementation(Document&);
> 
>-    void ref() { m_document.ref(); }
>-    void deref() { m_document.deref(); }
>+    REF_RETURN_TYPE ref() { m_document.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { m_document.deref(DEREF_DEFAULT_ARGUMENTS); }
>     Document& document() { return m_document; }
> 
>     WEBCORE_EXPORT ExceptionOr<Ref<DocumentType>> createDocumentType(const String& qualifiedName, const String& publicId, const String& systemId);
>diff --git a/Source/WebCore/dom/DataTransferItemList.h b/Source/WebCore/dom/DataTransferItemList.h
>index 13120e54ad3..8c568f709dd 100644
>--- a/Source/WebCore/dom/DataTransferItemList.h
>+++ b/Source/WebCore/dom/DataTransferItemList.h
>@@ -51,8 +51,8 @@ public:
>     ~DataTransferItemList();
> 
>     // DataTransfer owns DataTransferItemList, and DataTransfer is kept alive as long as DataTransferItemList is alive.
>-    void ref() { m_dataTransfer.ref(); }
>-    void deref() { m_dataTransfer.deref(); }
>+    REF_RETURN_TYPE ref() { m_dataTransfer.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { m_dataTransfer.deref(DEREF_DEFAULT_ARGUMENTS); }
>     DataTransfer& dataTransfer() { return m_dataTransfer; }
> 
>     // DOM API
>diff --git a/Source/WebCore/dom/DatasetDOMStringMap.cpp b/Source/WebCore/dom/DatasetDOMStringMap.cpp
>index ec6315c960b..e5a4ee1003a 100644
>--- a/Source/WebCore/dom/DatasetDOMStringMap.cpp
>+++ b/Source/WebCore/dom/DatasetDOMStringMap.cpp
>@@ -140,14 +140,15 @@ static AtomicString convertPropertyNameToAttributeName(const String& name)
>     return convertPropertyNameToAttributeName<UChar>(*nameImpl);
> }
> 
>-void DatasetDOMStringMap::ref()
>+REF_RETURN_TYPE DatasetDOMStringMap::ref()
> {
>     m_element.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void DatasetDOMStringMap::deref()
>+void DatasetDOMStringMap::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_element.deref();
>+    m_element.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> bool DatasetDOMStringMap::isSupportedPropertyName(const String& propertyName) const
>diff --git a/Source/WebCore/dom/DatasetDOMStringMap.h b/Source/WebCore/dom/DatasetDOMStringMap.h
>index 9100db8c88c..35fb01f837b 100644
>--- a/Source/WebCore/dom/DatasetDOMStringMap.h
>+++ b/Source/WebCore/dom/DatasetDOMStringMap.h
>@@ -40,8 +40,8 @@ public:
>     {
>     }
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     bool isSupportedPropertyName(const String& name) const;
>     Vector<String> supportedPropertyNames() const;
>diff --git a/Source/WebCore/dom/Document.cpp b/Source/WebCore/dom/Document.cpp
>index 527d6e4e276..ef4c413ba7b 100644
>--- a/Source/WebCore/dom/Document.cpp
>+++ b/Source/WebCore/dom/Document.cpp
>@@ -526,7 +526,7 @@ Document::Document(Frame* frame, const URL& url, unsigned documentClasses, unsig
>     , m_identifier(generateObjectIdentifier<DocumentIdentifierType>())
> {
>     ++DocumentCount;
>-//    WTFLogAlways("Created document %p %s (%d documents)", this, url.string().utf8().data(), DocumentCount);
>+    WTFLogAlways("Created document %p %s (%d documents)", this, url.string().utf8().data(), DocumentCount);
> 
>     auto addResult = allDocumentsMap().add(m_identifier, this);
>     ASSERT_UNUSED(addResult, addResult.isNewEntry);
>@@ -580,7 +580,7 @@ Ref<Document> Document::create(Document& contextDocument)
> Document::~Document()
> {
>     --DocumentCount;
>-//    WTFLogAlways("Destroying document %p %s (%d documents)", this, url().string().utf8().data(), DocumentCount);
>+    WTFLogAlways("Destroying document %p %s (%d documents)", this, url().string().utf8().data(), DocumentCount);
> 
>     if (m_logger)
>         m_logger->removeObserver(*this);
>@@ -717,6 +717,11 @@ void Document::removedLastRef()
>     }
> }
> 
>+unsigned Document::referencingNodeCount() const
>+{
>+    return m_referencingNodeCount;
>+}
>+
> void Document::commonTeardown()
> {
>     if (svgExtensions())
>diff --git a/Source/WebCore/dom/Document.h b/Source/WebCore/dom/Document.h
>index b236fd3deba..ffd3825072c 100644
>--- a/Source/WebCore/dom/Document.h
>+++ b/Source/WebCore/dom/Document.h
>@@ -362,7 +362,7 @@ public:
>         }
>     }
> 
>-    unsigned referencingNodeCount() const { return m_referencingNodeCount; }
>+    WEBCORE_EXPORT unsigned referencingNodeCount() const;
> 
>     void removedLastRef();
> 
>@@ -1473,8 +1473,8 @@ private:
>     Ref<Node> cloneNodeInternal(Document&, CloningOperation) final;
>     void cloneDataFromDocument(const Document&);
> 
>-    void refScriptExecutionContext() final { ref(); }
>-    void derefScriptExecutionContext() final { deref(); }
>+    REF_RETURN_TYPE refScriptExecutionContext() final { return ref(); }
>+    void derefScriptExecutionContext(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // The following addMessage function is deprecated.
>     // Callers should try to create the ConsoleMessage themselves.
>diff --git a/Source/WebCore/dom/ElementData.cpp b/Source/WebCore/dom/ElementData.cpp
>index 9515305584b..a5c597ece6d 100644
>--- a/Source/WebCore/dom/ElementData.cpp
>+++ b/Source/WebCore/dom/ElementData.cpp
>@@ -56,7 +56,9 @@ struct SameSizeAsElementData : public RefCounted<SameSizeAsElementData> {
>     void* refPtrs[3];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(ElementData) == sizeof(SameSizeAsElementData), element_attribute_data_should_stay_small);
>+#endif
> 
> static size_t sizeForShareableElementDataWithAttributeCount(unsigned count)
> {
>diff --git a/Source/WebCore/dom/ElementData.h b/Source/WebCore/dom/ElementData.h
>index f6d1eafd736..666bc97aeec 100644
>--- a/Source/WebCore/dom/ElementData.h
>+++ b/Source/WebCore/dom/ElementData.h
>@@ -80,7 +80,7 @@ class ElementData : public RefCounted<ElementData> {
> public:
>     // Override RefCounted's deref() to ensure operator delete is called on
>     // the appropriate subclass type.
>-    void deref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     static const unsigned attributeNotFound = static_cast<unsigned>(-1);
> 
>@@ -223,9 +223,9 @@ public:
>     AttributeVector m_attributeVector;
> };
> 
>-inline void ElementData::deref()
>+inline void ElementData::deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    if (!derefBase())
>+    if (!derefBase(DEREF_ARGUMENT_NAME))
>         return;
>     destroy();
> }
>diff --git a/Source/WebCore/dom/ElementRareData.cpp b/Source/WebCore/dom/ElementRareData.cpp
>index 478a8887e00..b12bb6449a5 100644
>--- a/Source/WebCore/dom/ElementRareData.cpp
>+++ b/Source/WebCore/dom/ElementRareData.cpp
>@@ -46,6 +46,8 @@ struct SameSizeAsElementRareData : NodeRareData {
>     void* pointers[8];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(ElementRareData) == sizeof(SameSizeAsElementRareData), "ElementRareData should stay small");
>+#endif
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/dom/EventTarget.h b/Source/WebCore/dom/EventTarget.h
>index 90b122ae74c..f85eb92ef85 100644
>--- a/Source/WebCore/dom/EventTarget.h
>+++ b/Source/WebCore/dom/EventTarget.h
>@@ -60,8 +60,8 @@ DOM_EVENT_TARGET_INTERFACES_FOR_EACH(DOM_EVENT_INTERFACE_DECLARE)
> 
> class EventTarget : public ScriptWrappable {
> public:
>-    void ref() { refEventTarget(); }
>-    void deref() { derefEventTarget(); }
>+    REF_RETURN_TYPE ref() { return refEventTarget(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefEventTarget(DEREF_ARGUMENT_NAME); }
> 
>     virtual EventTargetInterface eventTargetInterface() const = 0;
>     virtual ScriptExecutionContext* scriptExecutionContext() const = 0;
>@@ -125,8 +125,8 @@ protected:
>     const EventTargetData* eventTargetData() const;
> 
> private:
>-    virtual void refEventTarget() = 0;
>-    virtual void derefEventTarget() = 0;
>+    virtual REF_RETURN_TYPE refEventTarget() = 0;
>+    virtual void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) = 0;
>     
>     void fireEventListeners(Event&, EventListenerVector);
> 
>diff --git a/Source/WebCore/dom/MessagePort.cpp b/Source/WebCore/dom/MessagePort.cpp
>index 6f7fd36be3d..a43b08fd6ca 100644
>--- a/Source/WebCore/dom/MessagePort.cpp
>+++ b/Source/WebCore/dom/MessagePort.cpp
>@@ -50,12 +50,13 @@ static Lock& allMessagePortsLock()
>     return lock;
> }
> 
>-void MessagePort::ref() const
>+REF_RETURN_TYPE MessagePort::ref() const
> {
>     ++m_refCount;
>+    DEFAULT_REF_RETURN;
> }
> 
>-void MessagePort::deref() const
>+void MessagePort::deref(DEREF_ARGUMENT_TYPE) const
> {
>     // This custom deref() function ensures that as long as the lock to allMessagePortsLock is taken, no MessagePort will be destroyed.
>     // This allows isExistingMessagePortLocallyReachable and notifyMessageAvailable to easily query the map and manipulate MessagePort instances.
>diff --git a/Source/WebCore/dom/MessagePort.h b/Source/WebCore/dom/MessagePort.h
>index cb97d11c885..e47dd6cdf91 100644
>--- a/Source/WebCore/dom/MessagePort.h
>+++ b/Source/WebCore/dom/MessagePort.h
>@@ -78,8 +78,8 @@ public:
>     const MessagePortIdentifier& identifier() const { return m_identifier; }
>     const MessagePortIdentifier& remoteIdentifier() const { return m_remoteIdentifier; }
> 
>-    WEBCORE_EXPORT void ref() const;
>-    WEBCORE_EXPORT void deref() const;
>+    WEBCORE_EXPORT REF_RETURN_TYPE ref() const;
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) const;
> 
>     // ActiveDOMObject
>     const char* activeDOMObjectName() const final;
>@@ -93,8 +93,8 @@ public:
>     // EventTargetWithInlineData.
>     EventTargetInterface eventTargetInterface() const final { return MessagePortEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     explicit MessagePort(ScriptExecutionContext&, const MessagePortIdentifier& local, const MessagePortIdentifier& remote);
>diff --git a/Source/WebCore/dom/MutationObserver.cpp b/Source/WebCore/dom/MutationObserver.cpp
>index bc7fe7c8cff..890f738ece0 100644
>--- a/Source/WebCore/dom/MutationObserver.cpp
>+++ b/Source/WebCore/dom/MutationObserver.cpp
>@@ -85,19 +85,19 @@ MutationObserver::~MutationObserver()
>     WTFLogAlways("MutationObserver %p dtor - %d (activeMutationObservers size is %u, suspendedMutationObservers size is %u)", this, MutationObserverCount, activeMutationObservers().size(), suspendedMutationObservers().size());
> }
> 
>-void MutationObserver::ref()
>+REF_RETURN_TYPE MutationObserver::ref()
> {
>     CFRetain(m_treeTrap);
>-    RefCounted::ref();
>+    return RefCounted::ref();
> }
> 
>-void MutationObserver::deref()
>+void MutationObserver::deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>     CFRelease(m_treeTrap);
>     if (hasOneRef()) {
>         m_treeTrap = nullptr;
>     }
>-    RefCounted::deref();
>+    RefCounted::deref(DEREF_ARGUMENT_NAME);
> }
> 
> bool MutationObserver::validateOptions(MutationObserverOptions options)
>diff --git a/Source/WebCore/dom/MutationObserver.h b/Source/WebCore/dom/MutationObserver.h
>index a810e71d757..16e999b2cd7 100644
>--- a/Source/WebCore/dom/MutationObserver.h
>+++ b/Source/WebCore/dom/MutationObserver.h
>@@ -100,8 +100,8 @@ public:
> 
>     static void enqueueSlotChangeEvent(HTMLSlotElement&);
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
> private:
>     explicit MutationObserver(Ref<MutationCallback>&&);
>diff --git a/Source/WebCore/dom/NamedNodeMap.cpp b/Source/WebCore/dom/NamedNodeMap.cpp
>index 5b74a2b3598..9514471726f 100644
>--- a/Source/WebCore/dom/NamedNodeMap.cpp
>+++ b/Source/WebCore/dom/NamedNodeMap.cpp
>@@ -33,14 +33,15 @@ namespace WebCore {
> 
> using namespace HTMLNames;
> 
>-void NamedNodeMap::ref()
>+REF_RETURN_TYPE NamedNodeMap::ref()
> {
>     m_element.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void NamedNodeMap::deref()
>+void NamedNodeMap::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_element.deref();
>+    m_element.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> RefPtr<Attr> NamedNodeMap::getNamedItem(const AtomicString& name) const
>diff --git a/Source/WebCore/dom/NamedNodeMap.h b/Source/WebCore/dom/NamedNodeMap.h
>index 2cb59644998..4d33e33ea88 100644
>--- a/Source/WebCore/dom/NamedNodeMap.h
>+++ b/Source/WebCore/dom/NamedNodeMap.h
>@@ -40,8 +40,8 @@ public:
>     {
>     }
> 
>-    WEBCORE_EXPORT void ref();
>-    WEBCORE_EXPORT void deref();
>+    WEBCORE_EXPORT REF_RETURN_TYPE ref();
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     WEBCORE_EXPORT unsigned length() const;
>     WEBCORE_EXPORT RefPtr<Attr> item(unsigned index) const;
>diff --git a/Source/WebCore/dom/Node.cpp b/Source/WebCore/dom/Node.cpp
>index 86143d5b2ec..fb90f797483 100644
>--- a/Source/WebCore/dom/Node.cpp
>+++ b/Source/WebCore/dom/Node.cpp
>@@ -277,8 +277,7 @@ Node::Node(Document& document, ConstructionType type)
>     };
>     m_treeTrap = CFTreeCreate(kCFAllocatorDefault, &context);
> 
>-    ++NodeCount;
>-//    WTFLogAlways("Node %p ctor (tree trap %p) - %d", this, m_treeTrap, NodeCount);
>+    WTFLogAlways("Node %p ctor (tree trap %p) - %d", this, m_treeTrap, ++NodeCount);
> }
> 
> Node::~Node()
>@@ -321,12 +320,11 @@ Node::~Node()
>     }
> #endif
> 
>-    --NodeCount;
>-//    WTFLogAlways("Node %p dtor - %d", this, NodeCount);
>+    WTFLogAlways("Node %p dtor - %d", this, --NodeCount);
> }
> 
> 
>-void Node::ref()
>+REF_RETURN_TYPE Node::ref()
> {
>     ASSERT(isMainThread());
>     ASSERT(!m_deletionHasBegun);
>@@ -343,10 +341,16 @@ void Node::ref()
> 
>     ++m_refCount;
> 
>+
>     ASSERT(m_refCount == CFGetRetainCount(m_treeTrap));
>+#if ALLOW_REF_TRACING
>+    return m_refTracker.trackRef();
>+#else
>+    DEFAULT_REF_RETURN;
>+#endif
> }
> 
>-void Node::deref()
>+void Node::deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>     ASSERT(isMainThread());
>     ASSERT(m_refCount >= 0);
>@@ -356,6 +360,10 @@ void Node::deref()
> 
>     --m_refCount;
>     CFRelease(m_treeTrap);
>+    
>+#if ALLOW_REF_TRACING
>+    m_refTracker.trackDeref(DEREF_ARGUMENT_NAME);
>+#endif
> 
>     if (m_refCount <= 0 && !parentNode()) {
> #ifndef NDEBUG
>@@ -369,8 +377,6 @@ void Node::deref()
> }
> 
> 
>-
>-
> void Node::willBeDeletedFrom(Document& document)
> {
>     if (hasEventTargetData()) {
>@@ -807,14 +813,14 @@ LayoutRect Node::renderRect(bool* isReplaced)
>     return LayoutRect();    
> }
> 
>-void Node::refEventTarget()
>+REF_RETURN_TYPE Node::refEventTarget()
> {
>-    ref();
>+    return ref();
> }
> 
>-void Node::derefEventTarget()
>+void Node::derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    deref();
>+    deref(DEREF_ARGUMENT_NAME);
> }
> 
> void Node::adjustStyleValidity(Style::Validity validity, Style::InvalidationMode mode)
>diff --git a/Source/WebCore/dom/Node.h b/Source/WebCore/dom/Node.h
>index a6d53d86479..6aacca07b3b 100644
>--- a/Source/WebCore/dom/Node.h
>+++ b/Source/WebCore/dom/Node.h
>@@ -36,6 +36,7 @@
> #include <wtf/IsoMalloc.h>
> #include <wtf/ListHashSet.h>
> #include <wtf/MainThread.h>
>+#include <wtf/RefTracker.h>
> 
> // This needs to be here because Document.h also depends on it.
> #define DUMP_NODE_STATISTICS 1
>@@ -502,13 +503,16 @@ public:
>     // Perform the default action for an event.
>     virtual void defaultEventHandler(Event&);
> 
>-    WEBCORE_EXPORT void ref();
>-    WEBCORE_EXPORT void deref();
>+    WEBCORE_EXPORT REF_RETURN_TYPE ref();
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     bool hasOneRef() const;
>     int refCount() const;
> 
>     CFTreeRef treeTrap() const { return m_treeTrap; }
>+#if ALLOW_REF_TRACING
>+    const RefTracker& refTracker() const { return m_refTracker; }
>+#endif
> 
> #ifndef NDEBUG
>     bool m_deletionHasBegun { false };
>@@ -651,8 +655,9 @@ private:
> 
>     WEBCORE_EXPORT void removedLastRef();
> 
>-    void refEventTarget() final;
>-    void derefEventTarget() final;
>+    REF_RETURN_TYPE refEventTarget() final;
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final;
>+
>     bool isNode() const final;
> 
>     void trackForDebugging();
>@@ -683,6 +688,9 @@ private:
>     } m_data { nullptr };
> 
>     CFTreeRef m_treeTrap { nullptr };
>+#if ALLOW_REF_TRACING
>+    RefTracker m_refTracker;
>+#endif
> };
> 
> #ifndef NDEBUG
>diff --git a/Source/WebCore/dom/ScriptElement.cpp b/Source/WebCore/dom/ScriptElement.cpp
>index b37ba4d1083..2f659f9d740 100644
>--- a/Source/WebCore/dom/ScriptElement.cpp
>+++ b/Source/WebCore/dom/ScriptElement.cpp
>@@ -466,14 +466,15 @@ String ScriptElement::scriptContent() const
>     return TextNodeTraversal::childTextContent(m_element);
> }
> 
>-void ScriptElement::ref()
>+REF_RETURN_TYPE ScriptElement::ref()
> {
>     m_element.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void ScriptElement::deref()
>+void ScriptElement::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_element.deref();
>+    m_element.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> bool isScriptElement(Element& element)
>diff --git a/Source/WebCore/dom/ScriptElement.h b/Source/WebCore/dom/ScriptElement.h
>index a61dad45e9e..f3fe5ca0a47 100644
>--- a/Source/WebCore/dom/ScriptElement.h
>+++ b/Source/WebCore/dom/ScriptElement.h
>@@ -69,8 +69,8 @@ public:
>     enum class ScriptType { Classic, Module };
>     ScriptType scriptType() const { return m_isModuleScript ? ScriptType::Module : ScriptType::Classic; }
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
> protected:
>     ScriptElement(Element&, bool createdByParser, bool isEvaluated);
>diff --git a/Source/WebCore/dom/ScriptExecutionContext.h b/Source/WebCore/dom/ScriptExecutionContext.h
>index 2ad27ef37d7..eb7370218e5 100644
>--- a/Source/WebCore/dom/ScriptExecutionContext.h
>+++ b/Source/WebCore/dom/ScriptExecutionContext.h
>@@ -157,8 +157,8 @@ public:
> 
>     virtual void didLoadResourceSynchronously();
> 
>-    void ref() { refScriptExecutionContext(); }
>-    void deref() { derefScriptExecutionContext(); }
>+    REF_RETURN_TYPE ref() { return refScriptExecutionContext(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefScriptExecutionContext(DEREF_ARGUMENT_NAME); }
> 
>     class Task {
>         WTF_MAKE_FAST_ALLOCATED;
>@@ -291,8 +291,8 @@ private:
>     virtual void logExceptionToConsole(const String& errorMessage, const String& sourceURL, int lineNumber, int columnNumber, RefPtr<Inspector::ScriptCallStack>&&) = 0;
>     bool dispatchErrorEvent(const String& errorMessage, int lineNumber, int columnNumber, const String& sourceURL, JSC::Exception*, CachedScript*);
> 
>-    virtual void refScriptExecutionContext() = 0;
>-    virtual void derefScriptExecutionContext() = 0;
>+    virtual REF_RETURN_TYPE refScriptExecutionContext() = 0;
>+    virtual void derefScriptExecutionContext(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     RejectedPromiseTracker& ensureRejectedPromiseTrackerSlow();
> 
>diff --git a/Source/WebCore/dom/SpaceSplitString.h b/Source/WebCore/dom/SpaceSplitString.h
>index 057fbfc47e8..a69d6102bdb 100644
>--- a/Source/WebCore/dom/SpaceSplitString.h
>+++ b/Source/WebCore/dom/SpaceSplitString.h
>@@ -54,14 +54,15 @@ public:
>         return tokenArrayStart()[i];
>     }
> 
>-    void ref()
>+    REF_RETURN_TYPE ref()
>     {
>         ASSERT(isMainThread());
>         ASSERT(m_refCount);
>         ++m_refCount;
>+        DEFAULT_REF_RETURN;
>     }
> 
>-    void deref()
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS)
>     {
>         ASSERT(isMainThread());
>         ASSERT(m_refCount);
>diff --git a/Source/WebCore/fileapi/FileReader.h b/Source/WebCore/fileapi/FileReader.h
>index ef89f5bd6e0..ca4676e9219 100644
>--- a/Source/WebCore/fileapi/FileReader.h
>+++ b/Source/WebCore/fileapi/FileReader.h
>@@ -82,8 +82,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final { return FileReaderEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void didStartLoading() final;
>     void didReceiveData() final;
>diff --git a/Source/WebCore/html/CanvasBase.h b/Source/WebCore/html/CanvasBase.h
>index 5dfe29352e1..84177e8cfb0 100644
>--- a/Source/WebCore/html/CanvasBase.h
>+++ b/Source/WebCore/html/CanvasBase.h
>@@ -53,8 +53,8 @@ class CanvasBase {
> public:
>     virtual ~CanvasBase();
> 
>-    virtual void refCanvasBase() = 0;
>-    virtual void derefCanvasBase() = 0;
>+    virtual REF_RETURN_TYPE refCanvasBase() = 0;
>+    virtual void derefCanvasBase(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     virtual bool isHTMLCanvasElement() const { return false; }
>     virtual bool isOffscreenCanvas() const { return false; }
>diff --git a/Source/WebCore/html/DOMTokenList.h b/Source/WebCore/html/DOMTokenList.h
>index 3940f035eae..ff01a6c0ee7 100644
>--- a/Source/WebCore/html/DOMTokenList.h
>+++ b/Source/WebCore/html/DOMTokenList.h
>@@ -37,8 +37,8 @@ public:
> 
>     void associatedAttributeValueChanged(const AtomicString&);
> 
>-    void ref() { m_element.ref(); }
>-    void deref() { m_element.deref(); }
>+    REF_RETURN_TYPE ref() { m_element.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { m_element.deref(DEREF_DEFAULT_ARGUMENTS); }
> 
>     unsigned length() const;
>     const AtomicString& item(unsigned index) const;
>diff --git a/Source/WebCore/html/FormAssociatedElement.h b/Source/WebCore/html/FormAssociatedElement.h
>index d7219fc5137..7f3586cd1fe 100644
>--- a/Source/WebCore/html/FormAssociatedElement.h
>+++ b/Source/WebCore/html/FormAssociatedElement.h
>@@ -41,8 +41,8 @@ class FormAssociatedElement : public FormNamedItem {
> public:
>     virtual ~FormAssociatedElement();
> 
>-    void ref() { refFormAssociatedElement(); }
>-    void deref() { derefFormAssociatedElement(); }
>+    REF_RETURN_TYPE ref() { return refFormAssociatedElement(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefFormAssociatedElement(DEREF_ARGUMENT_NAME); }
> 
>     static HTMLFormElement* findAssociatedForm(const HTMLElement*, HTMLFormElement*);
>     HTMLFormElement* form() const { return m_form; }
>@@ -107,8 +107,8 @@ protected:
> 
> private:
>     virtual bool willValidate() const = 0;
>-    virtual void refFormAssociatedElement() = 0;
>-    virtual void derefFormAssociatedElement() = 0;
>+    virtual REF_RETURN_TYPE refFormAssociatedElement() = 0;
>+    virtual void derefFormAssociatedElement(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     void resetFormAttributeTargetObserver();
> 
>diff --git a/Source/WebCore/html/FormController.cpp b/Source/WebCore/html/FormController.cpp
>index 0f5b775bd02..5f880ac4063 100644
>--- a/Source/WebCore/html/FormController.cpp
>+++ b/Source/WebCore/html/FormController.cpp
>@@ -92,8 +92,8 @@ public:
>     bool isHashTableDeletedValue() const { return m_name == hashTableDeletedValue(); }
> 
> private:
>-    void ref() const;
>-    void deref() const;
>+    REF_RETURN_TYPE ref() const;
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) const;
> 
>     static AtomicStringImpl* hashTableDeletedValue() { return reinterpret_cast<AtomicStringImpl*>(-1); }
> 
>@@ -110,7 +110,7 @@ FormElementKey::FormElementKey(AtomicStringImpl* name, AtomicStringImpl* type)
> 
> FormElementKey::~FormElementKey()
> {
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> FormElementKey::FormElementKey(const FormElementKey& other)
>@@ -123,26 +123,27 @@ FormElementKey::FormElementKey(const FormElementKey& other)
> FormElementKey& FormElementKey::operator=(const FormElementKey& other)
> {
>     other.ref();
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
>     m_name = other.name();
>     m_type = other.type();
>     return *this;
> }
> 
>-void FormElementKey::ref() const
>+REF_RETURN_TYPE FormElementKey::ref() const
> {
>     if (name())
>         name()->ref();
>     if (type())
>         type()->ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void FormElementKey::deref() const
>+void FormElementKey::deref(DEREF_ARGUMENT_TYPE) const
> {
>     if (name())
>-        name()->deref();
>+        name()->deref(DEREF_DEFAULT_ARGUMENTS);
>     if (type())
>-        type()->deref();
>+        type()->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> inline bool operator==(const FormElementKey& a, const FormElementKey& b)
>diff --git a/Source/WebCore/html/HTMLCanvasElement.h b/Source/WebCore/html/HTMLCanvasElement.h
>index f88d6112de2..742086a62f1 100644
>--- a/Source/WebCore/html/HTMLCanvasElement.h
>+++ b/Source/WebCore/html/HTMLCanvasElement.h
>@@ -176,8 +176,8 @@ private:
> 
>     bool isGPUBased() const;
> 
>-    void refCanvasBase() final { HTMLElement::ref(); }
>-    void derefCanvasBase() final { HTMLElement::deref(); }
>+    REF_RETURN_TYPE refCanvasBase() final { return HTMLElement::ref(); }
>+    void derefCanvasBase(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { HTMLElement::deref(DEREF_ARGUMENT_NAME); }
> 
>     FloatRect m_dirtyRect;
>     mutable IntSize m_size;
>diff --git a/Source/WebCore/html/HTMLFormControlElement.h b/Source/WebCore/html/HTMLFormControlElement.h
>index d876573a298..bc3d081775c 100644
>--- a/Source/WebCore/html/HTMLFormControlElement.h
>+++ b/Source/WebCore/html/HTMLFormControlElement.h
>@@ -159,8 +159,8 @@ protected:
>     void didChangeForm() override;
> 
> private:
>-    void refFormAssociatedElement() override { ref(); }
>-    void derefFormAssociatedElement() override { deref(); }
>+    REF_RETURN_TYPE refFormAssociatedElement() override { return ref(); }
>+    void derefFormAssociatedElement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     bool matchesValidPseudoClass() const override;
>     bool matchesInvalidPseudoClass() const override;
>diff --git a/Source/WebCore/html/HTMLObjectElement.h b/Source/WebCore/html/HTMLObjectElement.h
>index 82f582dfd78..8a2ef780196 100644
>--- a/Source/WebCore/html/HTMLObjectElement.h
>+++ b/Source/WebCore/html/HTMLObjectElement.h
>@@ -88,8 +88,8 @@ private:
>     bool shouldAllowQuickTimeClassIdQuirk();
>     bool hasValidClassId();
> 
>-    void refFormAssociatedElement() final { ref(); }
>-    void derefFormAssociatedElement() final { deref(); }
>+    REF_RETURN_TYPE refFormAssociatedElement() final { return ref(); }
>+    void derefFormAssociatedElement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     FormNamedItem* asFormNamedItem() final { return this; }
>     HTMLObjectElement& asHTMLElement() final { return *this; }
>diff --git a/Source/WebCore/html/MediaController.h b/Source/WebCore/html/MediaController.h
>index 738cb5414cc..3b019b3320e 100644
>--- a/Source/WebCore/html/MediaController.h
>+++ b/Source/WebCore/html/MediaController.h
>@@ -91,8 +91,8 @@ private:
>     void scheduleTimeupdateEvent();
>     void startTimeupdateTimer();
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
>     EventTargetInterface eventTargetInterface() const final { return MediaControllerEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return &m_scriptExecutionContext; };
> 
>diff --git a/Source/WebCore/html/OffscreenCanvas.h b/Source/WebCore/html/OffscreenCanvas.h
>index c272ed6e999..1882371a5af 100644
>--- a/Source/WebCore/html/OffscreenCanvas.h
>+++ b/Source/WebCore/html/OffscreenCanvas.h
>@@ -87,11 +87,11 @@ private:
>     ScriptExecutionContext* scriptExecutionContext() const final { return CanvasBase::scriptExecutionContext(); }
> 
>     EventTargetInterface eventTargetInterface() const final { return OffscreenCanvasEventTargetInterfaceType; }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>-    void refCanvasBase() final { ref(); }
>-    void derefCanvasBase() final { deref(); }
>+    REF_RETURN_TYPE refCanvasBase() final { return ref(); }
>+    void derefCanvasBase(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     IntSize m_size;
> };
>diff --git a/Source/WebCore/html/canvas/CanvasRenderingContext.cpp b/Source/WebCore/html/canvas/CanvasRenderingContext.cpp
>index 8582a0674d6..cd53320b1a1 100644
>--- a/Source/WebCore/html/canvas/CanvasRenderingContext.cpp
>+++ b/Source/WebCore/html/canvas/CanvasRenderingContext.cpp
>@@ -44,12 +44,13 @@ CanvasRenderingContext::CanvasRenderingContext(CanvasBase& canvas)
> {
> }
> 
>-void CanvasRenderingContext::ref()
>+REF_RETURN_TYPE CanvasRenderingContext::ref()
> {
>     m_canvas.refCanvasBase();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void CanvasRenderingContext::deref()
>+void CanvasRenderingContext::deref(DEREF_ARGUMENT_TYPE)
> {
>     m_canvas.derefCanvasBase();
> }
>diff --git a/Source/WebCore/html/canvas/CanvasRenderingContext.h b/Source/WebCore/html/canvas/CanvasRenderingContext.h
>index 81cb55d77e3..ab8acd7e808 100644
>--- a/Source/WebCore/html/canvas/CanvasRenderingContext.h
>+++ b/Source/WebCore/html/canvas/CanvasRenderingContext.h
>@@ -46,8 +46,8 @@ class CanvasRenderingContext : public ScriptWrappable {
> public:
>     virtual ~CanvasRenderingContext() = default;
> 
>-    void ref();
>-    WEBCORE_EXPORT void deref();
>+    REF_RETURN_TYPE ref();
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
>     CanvasBase& canvasBase() const { return m_canvas; }
> 
>diff --git a/Source/WebCore/html/canvas/WebGLExtension.h b/Source/WebCore/html/canvas/WebGLExtension.h
>index 0f601fa82ff..a5acd7f00b3 100644
>--- a/Source/WebCore/html/canvas/WebGLExtension.h
>+++ b/Source/WebCore/html/canvas/WebGLExtension.h
>@@ -58,8 +58,8 @@ public:
>         ANGLEInstancedArraysName,
>     };
> 
>-    void ref() { m_context.ref(); }
>-    void deref() { m_context.deref(); }
>+    REF_RETURN_TYPE ref() { m_context.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { m_context.deref(DEREF_DEFAULT_ARGUMENTS); }
>     WebGLRenderingContextBase& context() { return m_context; }
> 
>     virtual ~WebGLExtension();
>diff --git a/Source/WebCore/html/track/TextTrack.h b/Source/WebCore/html/track/TextTrack.h
>index a7ef715a520..4e1f4ced1b2 100644
>--- a/Source/WebCore/html/track/TextTrack.h
>+++ b/Source/WebCore/html/track/TextTrack.h
>@@ -156,8 +156,8 @@ protected:
> private:
>     bool enabled() const override;
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     VTTRegionList& ensureVTTRegionList();
>     RefPtr<VTTRegionList> m_regions;
>diff --git a/Source/WebCore/html/track/TextTrackCue.h b/Source/WebCore/html/track/TextTrackCue.h
>index cfee47d844a..398a18c9eb1 100644
>--- a/Source/WebCore/html/track/TextTrackCue.h
>+++ b/Source/WebCore/html/track/TextTrackCue.h
>@@ -98,8 +98,8 @@ protected:
>     virtual void toJSON(JSON::Object&) const;
> 
> private:
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     using EventTarget::dispatchEvent;
>     void dispatchEvent(Event&) final;
>diff --git a/Source/WebCore/html/track/TrackListBase.h b/Source/WebCore/html/track/TrackListBase.h
>index f3d644dbc2e..f80053cb479 100644
>--- a/Source/WebCore/html/track/TrackListBase.h
>+++ b/Source/WebCore/html/track/TrackListBase.h
>@@ -75,8 +75,8 @@ private:
>     void scheduleTrackEvent(const AtomicString& eventName, Ref<TrackBase>&&);
> 
>     // EventTarget
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     HTMLMediaElement* m_element;
> 
>diff --git a/Source/WebCore/loader/DocumentThreadableLoader.h b/Source/WebCore/loader/DocumentThreadableLoader.h
>index 38382edf4cd..26364a2e441 100644
>--- a/Source/WebCore/loader/DocumentThreadableLoader.h
>+++ b/Source/WebCore/loader/DocumentThreadableLoader.h
>@@ -66,8 +66,8 @@ namespace WebCore {
>         using RefCounted<DocumentThreadableLoader>::deref;
> 
>     protected:
>-        void refThreadableLoader() override { ref(); }
>-        void derefThreadableLoader() override { deref(); }
>+        REF_RETURN_TYPE refThreadableLoader() override { return ref(); }
>+        void derefThreadableLoader(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     private:
>         enum BlockingBehavior {
>diff --git a/Source/WebCore/loader/ThreadableLoader.h b/Source/WebCore/loader/ThreadableLoader.h
>index 861748b7c7b..d76d7ca62ea 100644
>--- a/Source/WebCore/loader/ThreadableLoader.h
>+++ b/Source/WebCore/loader/ThreadableLoader.h
>@@ -77,16 +77,16 @@ namespace WebCore {
>         static RefPtr<ThreadableLoader> create(ScriptExecutionContext&, ThreadableLoaderClient&, ResourceRequest&&, const ThreadableLoaderOptions&, String&& referrer = String());
> 
>         virtual void cancel() = 0;
>-        void ref() { refThreadableLoader(); }
>-        void deref() { derefThreadableLoader(); }
>+        REF_RETURN_TYPE ref() { return refThreadableLoader(); }
>+        void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefThreadableLoader(DEREF_ARGUMENT_NAME); }
> 
>         static void logError(ScriptExecutionContext&, const ResourceError&, const String&);
> 
>     protected:
>         ThreadableLoader() = default;
>         virtual ~ThreadableLoader() = default;
>-        virtual void refThreadableLoader() = 0;
>-        virtual void derefThreadableLoader() = 0;
>+        virtual REF_RETURN_TYPE refThreadableLoader() = 0;
>+        virtual void derefThreadableLoader(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
>     };
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/loader/WorkerThreadableLoader.h b/Source/WebCore/loader/WorkerThreadableLoader.h
>index 03c1673b13f..591845e8cc9 100644
>--- a/Source/WebCore/loader/WorkerThreadableLoader.h
>+++ b/Source/WebCore/loader/WorkerThreadableLoader.h
>@@ -64,8 +64,8 @@ namespace WebCore {
>         using RefCounted<WorkerThreadableLoader>::deref;
> 
>     protected:
>-        void refThreadableLoader() override { ref(); }
>-        void derefThreadableLoader() override { deref(); }
>+        REF_RETURN_TYPE refThreadableLoader() override { return ref(); }
>+        void derefThreadableLoader(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     private:
>         // Creates a loader on the main thread and bridges communication between
>diff --git a/Source/WebCore/loader/appcache/DOMApplicationCache.h b/Source/WebCore/loader/appcache/DOMApplicationCache.h
>index cf6d2a9d99f..50f6481c844 100644
>--- a/Source/WebCore/loader/appcache/DOMApplicationCache.h
>+++ b/Source/WebCore/loader/appcache/DOMApplicationCache.h
>@@ -49,8 +49,8 @@ public:
> private:
>     explicit DOMApplicationCache(Frame&);
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     EventTargetInterface eventTargetInterface() const final { return DOMApplicationCacheEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final;
>diff --git a/Source/WebCore/page/AbstractDOMWindow.h b/Source/WebCore/page/AbstractDOMWindow.h
>index 64d45a8cacb..1e67203cdb2 100644
>--- a/Source/WebCore/page/AbstractDOMWindow.h
>+++ b/Source/WebCore/page/AbstractDOMWindow.h
>@@ -61,8 +61,8 @@ protected:
>     explicit AbstractDOMWindow(GlobalWindowIdentifier&&);
> 
>     EventTargetInterface eventTargetInterface() const final { return DOMWindowEventTargetInterfaceType; }
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
> private:
>     GlobalWindowIdentifier m_identifier;
>diff --git a/Source/WebCore/page/EventSource.h b/Source/WebCore/page/EventSource.h
>index 3792a9126f1..e4187cd6236 100644
>--- a/Source/WebCore/page/EventSource.h
>+++ b/Source/WebCore/page/EventSource.h
>@@ -75,8 +75,8 @@ private:
>     EventTargetInterface eventTargetInterface() const final { return EventSourceEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // ThreadableLoaderClient
>     void didReceiveResponse(unsigned long, const ResourceResponse&) final;
>diff --git a/Source/WebCore/page/Frame.cpp b/Source/WebCore/page/Frame.cpp
>index d86180359cd..9e81306d543 100644
>--- a/Source/WebCore/page/Frame.cpp
>+++ b/Source/WebCore/page/Frame.cpp
>@@ -1144,7 +1144,7 @@ void Frame::selfOnlyDeref()
>     if (hasOneRef())
>         dropChildren();
> 
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/page/Performance.h b/Source/WebCore/page/Performance.h
>index 24ab94bca29..bc837d50ca0 100644
>--- a/Source/WebCore/page/Performance.h
>+++ b/Source/WebCore/page/Performance.h
>@@ -97,8 +97,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final { return PerformanceEventTargetInterfaceType; }
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     bool isResourceTimingBufferFull() const;
>     void resourceTimingBufferFullTimerFired();
>diff --git a/Source/WebCore/page/VisualViewport.h b/Source/WebCore/page/VisualViewport.h
>index 47727d35aca..78eab0d3843 100644
>--- a/Source/WebCore/page/VisualViewport.h
>+++ b/Source/WebCore/page/VisualViewport.h
>@@ -58,8 +58,8 @@ public:
> private:
>     explicit VisualViewport(Frame*);
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void enqueueResizeEvent();
>     void enqueueScrollEvent();
>diff --git a/Source/WebCore/page/mac/PageMac.mm b/Source/WebCore/page/mac/PageMac.mm
>index 88b103fe443..d16242825c5 100644
>--- a/Source/WebCore/page/mac/PageMac.mm
>+++ b/Source/WebCore/page/mac/PageMac.mm
>@@ -78,6 +78,9 @@ void Page::platformInitialize()
>             WTFLogAlways("%u live documents:", Document::allDocuments().size());
>             for (const auto* document : Document::allDocuments()) {
>                 WTFLogAlways("Document %p (refCount %d) %s", document, document->refCount(), document->url().string().utf8().data());
>+                WTFLogAlways("Document %p reference stacks:\n");
>+                document->refTracker().dumpRemainingReferences();
>+                WTFLogAlways("\n");
>             }
>         });
>     });
>diff --git a/Source/WebCore/platform/Length.cpp b/Source/WebCore/platform/Length.cpp
>index 4658fd08e6d..623037312ef 100644
>--- a/Source/WebCore/platform/Length.cpp
>+++ b/Source/WebCore/platform/Length.cpp
>@@ -259,13 +259,14 @@ CalculationValue& Length::calculationValue() const
>     return calculationValues().get(m_calculationValueHandle);
> }
>     
>-void Length::ref() const
>+REF_RETURN_TYPE Length::ref() const
> {
>     ASSERT(isCalculated());
>     calculationValues().ref(m_calculationValueHandle);
>+    DEFAULT_REF_RETURN;
> }
> 
>-void Length::deref() const
>+void Length::deref(DEREF_ARGUMENT_TYPE) const
> {
>     ASSERT(isCalculated());
>     calculationValues().deref(m_calculationValueHandle);
>diff --git a/Source/WebCore/platform/Length.h b/Source/WebCore/platform/Length.h
>index bf14421af35..d774932afc7 100644
>--- a/Source/WebCore/platform/Length.h
>+++ b/Source/WebCore/platform/Length.h
>@@ -123,8 +123,8 @@ private:
> 
>     bool isCalculatedEqual(const Length&) const;
> 
>-    WEBCORE_EXPORT void ref() const;
>-    WEBCORE_EXPORT void deref() const;
>+    WEBCORE_EXPORT REF_RETURN_TYPE ref() const;
>+    WEBCORE_EXPORT void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) const;
>     
>     union {
>         int m_intValue;
>@@ -194,7 +194,7 @@ inline Length& Length::operator=(const Length& other)
>     if (other.isCalculated())
>         other.ref();
>     if (isCalculated())
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     memcpy(static_cast<void*>(this), static_cast<void*>(const_cast<Length*>(&other)), sizeof(Length));
>     return *this;
>@@ -206,7 +206,7 @@ inline Length& Length::operator=(Length&& other)
>         return *this;
> 
>     if (isCalculated())
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     memcpy(static_cast<void*>(this), static_cast<void*>(&other), sizeof(Length));
>     other.m_type = Auto;
>@@ -216,7 +216,7 @@ inline Length& Length::operator=(Length&& other)
> inline Length::~Length()
> {
>     if (isCalculated())
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> inline bool Length::operator==(const Length& other) const
>diff --git a/Source/WebCore/platform/ScrollableArea.cpp b/Source/WebCore/platform/ScrollableArea.cpp
>index 46e71eacbeb..bc1eed73a38 100644
>--- a/Source/WebCore/platform/ScrollableArea.cpp
>+++ b/Source/WebCore/platform/ScrollableArea.cpp
>@@ -57,7 +57,9 @@ struct SameSizeAsScrollableArea {
>     unsigned bitfields : 16;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(ScrollableArea) == sizeof(SameSizeAsScrollableArea), ScrollableArea_should_stay_small);
>+#endif
> 
> ScrollableArea::ScrollableArea()
>     : m_constrainsScrollingToContentEdge(true)
>diff --git a/Source/WebCore/platform/graphics/Color.cpp b/Source/WebCore/platform/graphics/Color.cpp
>index 5dd150f7a01..32b6df6c17b 100644
>--- a/Source/WebCore/platform/graphics/Color.cpp
>+++ b/Source/WebCore/platform/graphics/Color.cpp
>@@ -313,7 +313,7 @@ Color& Color::operator=(const Color& other)
>         return *this;
> 
>     if (isExtended())
>-        m_colorData.extendedColor->deref();
>+        m_colorData.extendedColor->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     m_colorData = other.m_colorData;
> 
>@@ -328,7 +328,7 @@ Color& Color::operator=(Color&& other)
>         return *this;
> 
>     if (isExtended())
>-        m_colorData.extendedColor->deref();
>+        m_colorData.extendedColor->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     m_colorData = other.m_colorData;
>     other.m_colorData.rgbaAndFlags = invalidRGBAColor;
>diff --git a/Source/WebCore/platform/graphics/Color.h b/Source/WebCore/platform/graphics/Color.h
>index 72fae22a586..fad5dd3483c 100644
>--- a/Source/WebCore/platform/graphics/Color.h
>+++ b/Source/WebCore/platform/graphics/Color.h
>@@ -177,7 +177,7 @@ public:
>     ~Color()
>     {
>         if (isExtended())
>-            m_colorData.extendedColor->deref();
>+            m_colorData.extendedColor->deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     static Color createUnchecked(int r, int g, int b)
>diff --git a/Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp b/Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp
>index b7d592a9c8a..be231f26f8c 100644
>--- a/Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp
>+++ b/Source/WebCore/platform/graphics/cg/ImageDecoderCG.cpp
>@@ -139,7 +139,7 @@ size_t sharedBufferGetBytesAtPosition(void* info, void* buffer, off_t position,
> void sharedBufferRelease(void* info)
> {
>     SharedBuffer* sharedBuffer = static_cast<SharedBuffer*>(info);
>-    sharedBuffer->deref();
>+    sharedBuffer->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> #endif
> 
>diff --git a/Source/WebCore/platform/graphics/cocoa/GPUBufferMetal.mm b/Source/WebCore/platform/graphics/cocoa/GPUBufferMetal.mm
>index ad46220b25a..45ea4cc4cd0 100644
>--- a/Source/WebCore/platform/graphics/cocoa/GPUBufferMetal.mm
>+++ b/Source/WebCore/platform/graphics/cocoa/GPUBufferMetal.mm
>@@ -52,9 +52,9 @@ GPUBuffer::GPUBuffer(GPUDevice* device, ArrayBufferView* data)
>     m_contents = ArrayBuffer::createFromBytes(pageAlignedCopy, data->byteLength(), [] (void* ptr) { Gigacage::alignedFree(Gigacage::Primitive, ptr); });
>     m_contents->ref();
>     ArrayBuffer* capturedContents = m_contents.get();
>-    m_buffer = adoptNS((MTLBuffer *)[device->platformDevice() newBufferWithBytesNoCopy:m_contents->data() length:pageAlignedSize options:MTLResourceOptionCPUCacheModeDefault deallocator:^(void*, NSUInteger) { capturedContents->deref(); }]);
>+    m_buffer = adoptNS((MTLBuffer *)[device->platformDevice() newBufferWithBytesNoCopy:m_contents->data() length:pageAlignedSize options:MTLResourceOptionCPUCacheModeDefault deallocator:^(void*, NSUInteger) { capturedContents->deref(DEREF_DEFAULT_ARGUMENTS); }]);
>     if (!m_buffer) {
>-        m_contents->deref();
>+        m_contents->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_contents = nullptr;
>     }
> }
>diff --git a/Source/WebCore/platform/mediastream/RealtimeOutgoingAudioSource.h b/Source/WebCore/platform/mediastream/RealtimeOutgoingAudioSource.h
>index aef0e886422..c54a2e3315a 100644
>--- a/Source/WebCore/platform/mediastream/RealtimeOutgoingAudioSource.h
>+++ b/Source/WebCore/platform/mediastream/RealtimeOutgoingAudioSource.h
>@@ -74,7 +74,7 @@ private:
>     rtc::RefCountReleaseStatus Release() const final
>     {
>         callOnMainThread([this] {
>-            deref();
>+            deref(DEREF_DEFAULT_ARGUMENTS);
>         });
>         return rtc::RefCountReleaseStatus::kOtherRefsRemained;
>     }
>diff --git a/Source/WebCore/platform/mediastream/RealtimeOutgoingVideoSource.h b/Source/WebCore/platform/mediastream/RealtimeOutgoingVideoSource.h
>index 17f86355cfd..96f2dd9a241 100644
>--- a/Source/WebCore/platform/mediastream/RealtimeOutgoingVideoSource.h
>+++ b/Source/WebCore/platform/mediastream/RealtimeOutgoingVideoSource.h
>@@ -55,7 +55,7 @@ public:
>     rtc::RefCountReleaseStatus Release() const final
>     {
>         callOnMainThread([this] {
>-            deref();
>+            deref(DEREF_DEFAULT_ARGUMENTS);
>         });
>         return rtc::RefCountReleaseStatus::kOtherRefsRemained;
>     }
>diff --git a/Source/WebCore/platform/network/AuthenticationClient.h b/Source/WebCore/platform/network/AuthenticationClient.h
>index 19f8bcd7c68..b2a3e386dc6 100644
>--- a/Source/WebCore/platform/network/AuthenticationClient.h
>+++ b/Source/WebCore/platform/network/AuthenticationClient.h
>@@ -39,15 +39,15 @@ public:
>     virtual void receivedRequestToPerformDefaultHandling(const AuthenticationChallenge&) = 0;
>     virtual void receivedChallengeRejection(const AuthenticationChallenge&) = 0;
> 
>-    void ref() { refAuthenticationClient(); }
>-    void deref() { derefAuthenticationClient(); }
>+    REF_RETURN_TYPE ref() { return refAuthenticationClient(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefAuthenticationClient(DEREF_ARGUMENT_NAME); }
> 
> protected:
>     virtual ~AuthenticationClient() = default;
> 
> private:
>-    virtual void refAuthenticationClient() = 0;
>-    virtual void derefAuthenticationClient() = 0;
>+    virtual REF_RETURN_TYPE refAuthenticationClient() = 0;
>+    virtual void derefAuthenticationClient(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> };
> 
> }
>diff --git a/Source/WebCore/platform/network/DataURLDecoder.cpp b/Source/WebCore/platform/network/DataURLDecoder.cpp
>index 88664235ac5..040b254c228 100644
>--- a/Source/WebCore/platform/network/DataURLDecoder.cpp
>+++ b/Source/WebCore/platform/network/DataURLDecoder.cpp
>@@ -103,7 +103,7 @@ private:
>         // Ensure DecodeTask gets deleted in the main thread.
>         m_decodeTask = nullptr;
> 
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     RunLoopTimer<DecodingResultDispatcher> m_timer;
>diff --git a/Source/WebCore/platform/network/ResourceHandle.h b/Source/WebCore/platform/network/ResourceHandle.h
>index fce796cadad..755e89a2dcb 100644
>--- a/Source/WebCore/platform/network/ResourceHandle.h
>+++ b/Source/WebCore/platform/network/ResourceHandle.h
>@@ -229,8 +229,8 @@ private:
>     bool start();
>     static void platformLoadResourceSynchronously(NetworkingContext*, const ResourceRequest&, StoredCredentialsPolicy, ResourceError&, ResourceResponse&, Vector<char>& data);
> 
>-    void refAuthenticationClient() override { ref(); }
>-    void derefAuthenticationClient() override { deref(); }
>+    REF_RETURN_TYPE refAuthenticationClient() override { return ref(); }
>+    void derefAuthenticationClient(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
> #if PLATFORM(COCOA) || USE(CFURLCONNECTION)
>     enum class SchedulingBehavior { Asynchronous, Synchronous };
>diff --git a/Source/WebCore/platform/network/cf/SocketStreamHandleImplCFNet.cpp b/Source/WebCore/platform/network/cf/SocketStreamHandleImplCFNet.cpp
>index 9ed5aa0c9d9..1ee9df8709f 100644
>--- a/Source/WebCore/platform/network/cf/SocketStreamHandleImplCFNet.cpp
>+++ b/Source/WebCore/platform/network/cf/SocketStreamHandleImplCFNet.cpp
>@@ -165,7 +165,7 @@ void* SocketStreamHandleImpl::retainSocketStreamHandle(void* info)
> void SocketStreamHandleImpl::releaseSocketStreamHandle(void* info)
> {
>     SocketStreamHandle* handle = static_cast<SocketStreamHandle*>(info);
>-    handle->deref();
>+    handle->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> CFStringRef SocketStreamHandleImpl::copyPACExecutionDescription(void*)
>diff --git a/Source/WebCore/platform/text/BidiContext.cpp b/Source/WebCore/platform/text/BidiContext.cpp
>index c9f0f813bcb..221dec09b3c 100644
>--- a/Source/WebCore/platform/text/BidiContext.cpp
>+++ b/Source/WebCore/platform/text/BidiContext.cpp
>@@ -31,7 +31,9 @@ struct SameSizeAsBidiContext : public RefCounted<SameSizeAsBidiContext> {
>     void* parent;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(BidiContext) == sizeof(SameSizeAsBidiContext), BidiContext_should_stay_small);
>+#endif
> 
> inline BidiContext::BidiContext(unsigned char level, UCharDirection direction, bool override, BidiEmbeddingSource source, BidiContext* parent)
>     : m_level(level)
>diff --git a/Source/WebCore/rendering/FloatingObjects.cpp b/Source/WebCore/rendering/FloatingObjects.cpp
>index 3f7db1b1f1d..44f6191be08 100644
>--- a/Source/WebCore/rendering/FloatingObjects.cpp
>+++ b/Source/WebCore/rendering/FloatingObjects.cpp
>@@ -40,7 +40,9 @@ struct SameSizeAsFloatingObject {
>     uint32_t bitfields : 8;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(FloatingObject) == sizeof(SameSizeAsFloatingObject), FloatingObject_should_stay_small);
>+#endif
> 
> FloatingObject::FloatingObject(RenderBox& renderer)
>     : m_renderer(makeWeakPtr(renderer))
>diff --git a/Source/WebCore/rendering/InlineFlowBox.cpp b/Source/WebCore/rendering/InlineFlowBox.cpp
>index 80f3c91e3e8..27cf54aacbd 100644
>--- a/Source/WebCore/rendering/InlineFlowBox.cpp
>+++ b/Source/WebCore/rendering/InlineFlowBox.cpp
>@@ -51,7 +51,9 @@ struct SameSizeAsInlineFlowBox : public InlineBox {
>     uint32_t bitfields : 23;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(InlineFlowBox) == sizeof(SameSizeAsInlineFlowBox), InlineFlowBox_should_stay_small);
>+#endif
> 
> #if !ASSERT_WITH_SECURITY_IMPLICATION_DISABLED
> 
>diff --git a/Source/WebCore/rendering/RenderBox.cpp b/Source/WebCore/rendering/RenderBox.cpp
>index d97318c919a..0a665630e70 100644
>--- a/Source/WebCore/rendering/RenderBox.cpp
>+++ b/Source/WebCore/rendering/RenderBox.cpp
>@@ -92,7 +92,9 @@ struct SameSizeAsRenderBox : public RenderBoxModelObject {
>     void* pointers[2];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(RenderBox) == sizeof(SameSizeAsRenderBox), RenderBox_should_stay_small);
>+#endif
> 
> using namespace HTMLNames;
> 
>diff --git a/Source/WebCore/rendering/RenderObject.cpp b/Source/WebCore/rendering/RenderObject.cpp
>index cdb0262053b..5aa2a6c6645 100644
>--- a/Source/WebCore/rendering/RenderObject.cpp
>+++ b/Source/WebCore/rendering/RenderObject.cpp
>@@ -108,7 +108,9 @@ struct SameSizeAsRenderObject {
>     unsigned m_bitfields;
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(RenderObject) == sizeof(SameSizeAsRenderObject), RenderObject_should_stay_small);
>+#endif
> 
> DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, renderObjectCounter, ("RenderObject"));
> 
>@@ -1477,7 +1479,7 @@ void RenderObject::destroy()
>     willBeDestroyed();
> 
>     if (is<RenderWidget>(*this)) {
>-        downcast<RenderWidget>(*this).deref();
>+        downcast<RenderWidget>(*this).deref(DEREF_DEFAULT_ARGUMENTS);
>         return;
>     }
>     delete this;
>diff --git a/Source/WebCore/rendering/RenderWidget.h b/Source/WebCore/rendering/RenderWidget.h
>index 8ae3d2c65b2..4fa35e0051b 100644
>--- a/Source/WebCore/rendering/RenderWidget.h
>+++ b/Source/WebCore/rendering/RenderWidget.h
>@@ -71,8 +71,8 @@ public:
> 
>     bool requiresAcceleratedCompositing() const;
> 
>-    void ref() { ++m_refCount; }
>-    void deref();
>+    REF_RETURN_TYPE ref() { ++m_refCount;  DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
> protected:
>     RenderWidget(HTMLFrameOwnerElement&, RenderStyle&&);
>@@ -104,7 +104,7 @@ private:
>     unsigned m_refCount { 1 };
> };
> 
>-inline void RenderWidget::deref()
>+inline void RenderWidget::deref(DEREF_ARGUMENT_TYPE)
> {
>     ASSERT(m_refCount);
>     if (!--m_refCount)
>diff --git a/Source/WebCore/rendering/RootInlineBox.cpp b/Source/WebCore/rendering/RootInlineBox.cpp
>index 08690b9c26d..b07ced47743 100644
>--- a/Source/WebCore/rendering/RootInlineBox.cpp
>+++ b/Source/WebCore/rendering/RootInlineBox.cpp
>@@ -50,7 +50,9 @@ struct SameSizeAsRootInlineBox : public InlineFlowBox {
>     void* pointers[4];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(RootInlineBox) == sizeof(SameSizeAsRootInlineBox), RootInlineBox_should_stay_small);
>+#endif
> 
> typedef WTF::HashMap<const RootInlineBox*, std::unique_ptr<EllipsisBox>> EllipsisBoxMap;
> static EllipsisBoxMap* gEllipsisBoxMap;
>diff --git a/Source/WebCore/rendering/style/RenderStyle.cpp b/Source/WebCore/rendering/style/RenderStyle.cpp
>index f61988f24c2..b309e953d7a 100644
>--- a/Source/WebCore/rendering/style/RenderStyle.cpp
>+++ b/Source/WebCore/rendering/style/RenderStyle.cpp
>@@ -81,7 +81,9 @@ struct SameSizeAsRenderStyle {
> #endif
> };
> 
>+#ifndef ALLOW_REF_TRACING
> static_assert(sizeof(RenderStyle) == sizeof(SameSizeAsRenderStyle), "RenderStyle should stay small");
>+#endif
> 
> RenderStyle& RenderStyle::defaultStyle()
> {
>diff --git a/Source/WebCore/rendering/style/StyleRareInheritedData.cpp b/Source/WebCore/rendering/style/StyleRareInheritedData.cpp
>index cbef75e42e4..5315a1012f4 100644
>--- a/Source/WebCore/rendering/style/StyleRareInheritedData.cpp
>+++ b/Source/WebCore/rendering/style/StyleRareInheritedData.cpp
>@@ -68,7 +68,9 @@ struct GreaterThanOrSameSizeAsStyleRareInheritedData : public RefCounted<Greater
>     void* customPropertyDataRefs[1];
> };
> 
>+#ifndef ALLOW_REF_TRACING
> COMPILE_ASSERT(sizeof(StyleRareInheritedData) <= sizeof(GreaterThanOrSameSizeAsStyleRareInheritedData), StyleRareInheritedData_should_bit_pack);
>+#endif
> 
> StyleRareInheritedData::StyleRareInheritedData()
>     : listStyleImage(RenderStyle::initialListStyleImage())
>diff --git a/Source/WebCore/testing/MockContentFilterSettings.h b/Source/WebCore/testing/MockContentFilterSettings.h
>index 33d21a0efa9..80c953d0923 100644
>--- a/Source/WebCore/testing/MockContentFilterSettings.h
>+++ b/Source/WebCore/testing/MockContentFilterSettings.h
>@@ -51,8 +51,8 @@ public:
>     static const char* unblockURLHost() { return "mock-unblock"; }
> 
>     // Trick the generated bindings into thinking we're RefCounted.
>-    void ref() { }
>-    void deref() { }
>+    REF_RETURN_TYPE ref() {  DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { }
> 
>     bool enabled() const { return m_enabled; }
>     WTF_EXPORT_PRIVATE void setEnabled(bool);
>diff --git a/Source/WebCore/testing/MockCredentialsMessenger.cpp b/Source/WebCore/testing/MockCredentialsMessenger.cpp
>index 32d7080b10a..33178946b74 100644
>--- a/Source/WebCore/testing/MockCredentialsMessenger.cpp
>+++ b/Source/WebCore/testing/MockCredentialsMessenger.cpp
>@@ -61,14 +61,15 @@ void MockCredentialsMessenger::setAssertionReturnBundle(const BufferSource& cred
>     m_userHandle.append(userHandle.data(), userHandle.length());
> }
> 
>-void MockCredentialsMessenger::ref()
>+REF_RETURN_TYPE MockCredentialsMessenger::ref()
> {
>     m_internals.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void MockCredentialsMessenger::deref()
>+void MockCredentialsMessenger::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_internals.deref();
>+    m_internals.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void MockCredentialsMessenger::makeCredential(const Vector<uint8_t>&, const PublicKeyCredentialCreationOptions&, CreationCompletionHandler&& handler)
>diff --git a/Source/WebCore/testing/MockCredentialsMessenger.h b/Source/WebCore/testing/MockCredentialsMessenger.h
>index b4b08df4eaa..2afae352ff0 100644
>--- a/Source/WebCore/testing/MockCredentialsMessenger.h
>+++ b/Source/WebCore/testing/MockCredentialsMessenger.h
>@@ -46,8 +46,8 @@ public:
>     void setCreationReturnBundle(const BufferSource& credentialId, const BufferSource& attestationObject);
>     void setAssertionReturnBundle(const BufferSource& credentialId, const BufferSource& authenticatorData, const BufferSource& signature, const BufferSource& userHandle);
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> 
> private:
>     void makeCredential(const Vector<uint8_t>&, const PublicKeyCredentialCreationOptions&, CreationCompletionHandler&&) final;
>diff --git a/Source/WebCore/testing/MockPaymentCoordinator.h b/Source/WebCore/testing/MockPaymentCoordinator.h
>index 1f7d068d1cc..ad05f220434 100644
>--- a/Source/WebCore/testing/MockPaymentCoordinator.h
>+++ b/Source/WebCore/testing/MockPaymentCoordinator.h
>@@ -51,8 +51,8 @@ public:
>     const ApplePayLineItem& total() const { return m_total; }
>     const Vector<ApplePayLineItem>& lineItems() const { return m_lineItems; }
> 
>-    void ref() const { }
>-    void deref() const { }
>+    REF_RETURN_TYPE ref() const { DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) const { }
> 
> private:
>     bool supportsVersion(unsigned) final;
>diff --git a/Source/WebCore/workers/AbstractWorker.h b/Source/WebCore/workers/AbstractWorker.h
>index 900c2cb4046..76136076225 100644
>--- a/Source/WebCore/workers/AbstractWorker.h
>+++ b/Source/WebCore/workers/AbstractWorker.h
>@@ -51,8 +51,8 @@ protected:
>     intptr_t asID() const { return reinterpret_cast<intptr_t>(this); }
> 
> private:
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> };
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/workers/WorkerGlobalScope.h b/Source/WebCore/workers/WorkerGlobalScope.h
>index bac0db88dad..db9e0e13736 100644
>--- a/Source/WebCore/workers/WorkerGlobalScope.h
>+++ b/Source/WebCore/workers/WorkerGlobalScope.h
>@@ -127,11 +127,11 @@ protected:
>     void applyContentSecurityPolicyResponseHeaders(const ContentSecurityPolicyResponseHeaders&);
> 
> private:
>-    void refScriptExecutionContext() final { ref(); }
>-    void derefScriptExecutionContext() final { deref(); }
>+    REF_RETURN_TYPE refScriptExecutionContext() final { return ref(); }
>+    void derefScriptExecutionContext(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     void logExceptionToConsole(const String& errorMessage, const String& sourceURL, int lineNumber, int columnNumber, RefPtr<Inspector::ScriptCallStack>&&) final;
> 
>diff --git a/Source/WebCore/workers/WorkerMessagingProxy.cpp b/Source/WebCore/workers/WorkerMessagingProxy.cpp
>index 1540d77d5be..25c03afbcf1 100644
>--- a/Source/WebCore/workers/WorkerMessagingProxy.cpp
>+++ b/Source/WebCore/workers/WorkerMessagingProxy.cpp
>@@ -256,7 +256,7 @@ void WorkerMessagingProxy::workerGlobalScopeDestroyedInternal()
> 
>     // This balances the original ref in construction.
>     if (m_mayBeDestroyed)
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void WorkerMessagingProxy::terminateWorkerGlobalScope()
>diff --git a/Source/WebCore/workers/service/ServiceWorker.h b/Source/WebCore/workers/service/ServiceWorker.h
>index 9b9bcc8a22f..197b51d0668 100644
>--- a/Source/WebCore/workers/service/ServiceWorker.h
>+++ b/Source/WebCore/workers/service/ServiceWorker.h
>@@ -70,8 +70,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final;
>     ScriptExecutionContext* scriptExecutionContext() const final;
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // ActiveDOMObject.
>     const char* activeDOMObjectName() const final;
>diff --git a/Source/WebCore/workers/service/ServiceWorkerContainer.cpp b/Source/WebCore/workers/service/ServiceWorkerContainer.cpp
>index 5edbc53b505..05d36df43c8 100644
>--- a/Source/WebCore/workers/service/ServiceWorkerContainer.cpp
>+++ b/Source/WebCore/workers/service/ServiceWorkerContainer.cpp
>@@ -71,14 +71,15 @@ ServiceWorkerContainer::~ServiceWorkerContainer()
> #endif
> }
> 
>-void ServiceWorkerContainer::refEventTarget()
>+REF_RETURN_TYPE ServiceWorkerContainer::refEventTarget()
> {
>     m_navigator.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void ServiceWorkerContainer::derefEventTarget()
>+void ServiceWorkerContainer::derefEventTarget(DEREF_ARGUMENT_TYPE)
> {
>-    m_navigator.deref();
>+    m_navigator.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> auto ServiceWorkerContainer::ready() -> ReadyPromise&
>diff --git a/Source/WebCore/workers/service/ServiceWorkerContainer.h b/Source/WebCore/workers/service/ServiceWorkerContainer.h
>index ad3851be809..84ce2b3a1eb 100644
>--- a/Source/WebCore/workers/service/ServiceWorkerContainer.h
>+++ b/Source/WebCore/workers/service/ServiceWorkerContainer.h
>@@ -79,8 +79,8 @@ public:
> 
>     void startMessages();
> 
>-    void ref() final { refEventTarget(); }
>-    void deref() final { derefEventTarget(); }
>+    REF_RETURN_TYPE ref() final { return refEventTarget(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { derefEventTarget(DEREF_ARGUMENT_NAME); }
> 
>     bool isStopped() const { return m_isStopped; };
> 
>@@ -110,8 +110,10 @@ private:
>     bool canSuspendForDocumentSuspension() const final;
>     ScriptExecutionContext* scriptExecutionContext() const final { return ActiveDOMObject::scriptExecutionContext(); }
>     EventTargetInterface eventTargetInterface() const final { return ServiceWorkerContainerEventTargetInterfaceType; }
>-    void refEventTarget() final;
>-    void derefEventTarget() final;
>+
>+    REF_RETURN_TYPE refEventTarget() final;
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final;
>+
>     void stop() final;
> 
>     std::unique_ptr<ReadyPromise> m_readyPromise;
>diff --git a/Source/WebCore/workers/service/ServiceWorkerJobClient.h b/Source/WebCore/workers/service/ServiceWorkerJobClient.h
>index 6737ecaf1ec..c83cc803787 100644
>--- a/Source/WebCore/workers/service/ServiceWorkerJobClient.h
>+++ b/Source/WebCore/workers/service/ServiceWorkerJobClient.h
>@@ -54,8 +54,8 @@ public:
> 
>     virtual SWServerConnectionIdentifier connectionIdentifier() = 0;
> 
>-    virtual void ref() = 0;
>-    virtual void deref() = 0;
>+    virtual REF_RETURN_TYPE ref() = 0;
>+    virtual void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> };
> 
> } // namespace WebCore
>diff --git a/Source/WebCore/workers/service/ServiceWorkerRegistration.h b/Source/WebCore/workers/service/ServiceWorkerRegistration.h
>index 4372887349d..c14e20f6066 100644
>--- a/Source/WebCore/workers/service/ServiceWorkerRegistration.h
>+++ b/Source/WebCore/workers/service/ServiceWorkerRegistration.h
>@@ -82,8 +82,8 @@ private:
> 
>     EventTargetInterface eventTargetInterface() const final;
>     ScriptExecutionContext* scriptExecutionContext() const final;
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     // ActiveDOMObject.
>     const char* activeDOMObjectName() const final;
>diff --git a/Source/WebCore/xml/XMLHttpRequest.h b/Source/WebCore/xml/XMLHttpRequest.h
>index e32d01335ca..fc223df0cf6 100644
>--- a/Source/WebCore/xml/XMLHttpRequest.h
>+++ b/Source/WebCore/xml/XMLHttpRequest.h
>@@ -127,8 +127,8 @@ private:
>     void stop() override;
>     const char* activeDOMObjectName() const override;
> 
>-    void refEventTarget() override { ref(); }
>-    void derefEventTarget() override { deref(); }
>+    REF_RETURN_TYPE refEventTarget() override { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { deref(DEREF_ARGUMENT_NAME); }
> 
>     Document* document() const;
>     SecurityOrigin* securityOrigin() const;
>diff --git a/Source/WebCore/xml/XMLHttpRequestUpload.h b/Source/WebCore/xml/XMLHttpRequestUpload.h
>index e9ebb58232d..ae57f7c7300 100644
>--- a/Source/WebCore/xml/XMLHttpRequestUpload.h
>+++ b/Source/WebCore/xml/XMLHttpRequestUpload.h
>@@ -35,15 +35,15 @@ class XMLHttpRequestUpload final : public XMLHttpRequestEventTarget {
> public:
>     explicit XMLHttpRequestUpload(XMLHttpRequest&);
> 
>-    void ref() { m_request.ref(); }
>-    void deref() { m_request.deref(); }
>+    REF_RETURN_TYPE ref() { m_request.ref(); DEFAULT_REF_RETURN; }
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) { m_request.deref(DEREF_DEFAULT_ARGUMENTS); }
> 
>     void dispatchThrottledProgressEvent(bool lengthComputable, unsigned long long loaded, unsigned long long total);
>     void dispatchProgressEvent(const AtomicString& type);
> 
> private:
>-    void refEventTarget() final { ref(); }
>-    void derefEventTarget() final { deref(); }
>+    REF_RETURN_TYPE refEventTarget() final { return ref(); }
>+    void derefEventTarget(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) final { deref(DEREF_ARGUMENT_NAME); }
> 
>     EventTargetInterface eventTargetInterface() const final { return XMLHttpRequestUploadEventTargetInterfaceType; }
>     ScriptExecutionContext* scriptExecutionContext() const final { return m_request.scriptExecutionContext(); }
>diff --git a/Source/WebCore/xml/XPathGrammar.cpp b/Source/WebCore/xml/XPathGrammar.cpp
>index 31df1c0d158..1a5da5daa23 100644
>--- a/Source/WebCore/xml/XPathGrammar.cpp
>+++ b/Source/WebCore/xml/XPathGrammar.cpp
>@@ -1203,32 +1203,32 @@ yydestruct (yymsg, yytype, yyvaluep, parser)
>     {
>       case 10: /* "FUNCTIONNAME" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1205 "./XPathGrammar.cpp"
>     break;
>       case 11: /* "LITERAL" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1210 "./XPathGrammar.cpp"
>     break;
>       case 12: /* "NAMETEST" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1215 "./XPathGrammar.cpp"
>     break;
>       case 13: /* "NUMBER" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1220 "./XPathGrammar.cpp"
>     break;
>       case 14: /* "NODETYPE" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1225 "./XPathGrammar.cpp"
>     break;
>       case 15: /* "VARIABLEREFERENCE" */
> #line 80 "WebCore/xml/XPathGrammar.y"
>-    { if ((yyvaluep->string)) (yyvaluep->string)->deref(); };
>+    { if ((yyvaluep->string)) (yyvaluep->string)->deref(DEREF_DEFAULT_ARGUMENTS); };
> #line 1230 "./XPathGrammar.cpp"
>     break;
>       case 35: /* "Expr" */
>diff --git a/Source/WebCore/xml/XPathGrammar.y b/Source/WebCore/xml/XPathGrammar.y
>index 4eb20b92a56..2dfa8eac5a6 100644
>--- a/Source/WebCore/xml/XPathGrammar.y
>+++ b/Source/WebCore/xml/XPathGrammar.y
>@@ -77,7 +77,7 @@ using namespace XPath;
> %left OR AND
> 
> %token <string> FUNCTIONNAME LITERAL NAMETEST NUMBER NODETYPE VARIABLEREFERENCE
>-%destructor { if ($$) $$->deref(); } FUNCTIONNAME LITERAL NAMETEST NUMBER NODETYPE VARIABLEREFERENCE
>+%destructor { if ($$) $$->deref(DEREF_DEFAULT_ARGUMENTS); } FUNCTIONNAME LITERAL NAMETEST NUMBER NODETYPE VARIABLEREFERENCE
> 
> %token <axis> AXISNAME
> %type <axis> AxisSpecifier
>diff --git a/Source/WebCore/xml/parser/XMLDocumentParser.cpp b/Source/WebCore/xml/parser/XMLDocumentParser.cpp
>index 1f28a8eba59..1e31642297d 100644
>--- a/Source/WebCore/xml/parser/XMLDocumentParser.cpp
>+++ b/Source/WebCore/xml/parser/XMLDocumentParser.cpp
>@@ -77,7 +77,7 @@ void XMLDocumentParser::popCurrentNode()
>     ASSERT(m_currentNodeStack.size());
> 
>     if (m_currentNode != document())
>-        m_currentNode->deref();
>+        m_currentNode->deref(DEREF_DEFAULT_ARGUMENTS);
> 
>     m_currentNode = m_currentNodeStack.last();
>     m_currentNodeStack.removeLast();
>@@ -86,15 +86,15 @@ void XMLDocumentParser::popCurrentNode()
> void XMLDocumentParser::clearCurrentNodeStack()
> {
>     if (m_currentNode && m_currentNode != document())
>-        m_currentNode->deref();
>+        m_currentNode->deref(DEREF_DEFAULT_ARGUMENTS);
>     m_currentNode = nullptr;
>     m_leafTextNode = nullptr;
> 
>     if (m_currentNodeStack.size()) { // Aborted parsing.
>         for (size_t i = m_currentNodeStack.size() - 1; i != 0; --i)
>-            m_currentNodeStack[i]->deref();
>+            m_currentNodeStack[i]->deref(DEREF_DEFAULT_ARGUMENTS);
>         if (m_currentNodeStack[0] && m_currentNodeStack[0] != document())
>-            m_currentNodeStack[0]->deref();
>+            m_currentNodeStack[0]->deref(DEREF_DEFAULT_ARGUMENTS);
>         m_currentNodeStack.clear();
>     }
> }
>diff --git a/Source/WebKit/Platform/IPC/mac/ConnectionMac.mm b/Source/WebKit/Platform/IPC/mac/ConnectionMac.mm
>index 1f7b7b79865..91319bd4c10 100644
>--- a/Source/WebKit/Platform/IPC/mac/ConnectionMac.mm
>+++ b/Source/WebKit/Platform/IPC/mac/ConnectionMac.mm
>@@ -238,7 +238,7 @@ bool Connection::open()
>         if (m_sendSource)
>             dispatch_resume(m_sendSource);
> 
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> 
>     return true;
>diff --git a/Source/WebKit/Shared/API/APIObject.h b/Source/WebKit/Shared/API/APIObject.h
>index 1f6003ff5f4..2cea503f2c8 100644
>--- a/Source/WebKit/Shared/API/APIObject.h
>+++ b/Source/WebKit/Shared/API/APIObject.h
>@@ -217,8 +217,8 @@ public:
> 
>     NSObject *wrapper() { return m_wrapper; }
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS);
> #endif // DELEGATE_REF_COUNTING_TO_COCOA
> 
>     static void* wrap(API::Object*);
>diff --git a/Source/WebKit/Shared/API/c/WKType.cpp b/Source/WebKit/Shared/API/c/WKType.cpp
>index fd20e6fff1e..4637935d525 100644
>--- a/Source/WebKit/Shared/API/c/WKType.cpp
>+++ b/Source/WebKit/Shared/API/c/WKType.cpp
>@@ -45,5 +45,5 @@ WKTypeRef WKRetain(WKTypeRef typeRef)
> 
> void WKRelease(WKTypeRef typeRef)
> {
>-    toImpl(typeRef)->deref();
>+    toImpl(typeRef)->deref(DEREF_DEFAULT_ARGUMENTS);
> }
>diff --git a/Source/WebKit/Shared/Cocoa/APIObject.mm b/Source/WebKit/Shared/Cocoa/APIObject.mm
>index 6899ca5627a..d27c3bca3b0 100644
>--- a/Source/WebKit/Shared/Cocoa/APIObject.mm
>+++ b/Source/WebKit/Shared/Cocoa/APIObject.mm
>@@ -92,12 +92,13 @@ static const size_t maximumExtraSpaceForAlignment = minimumObjectAlignment - ali
> 
> namespace API {
> 
>-void Object::ref()
>+REF_RETURN_TYPE Object::ref()
> {
>     CFRetain(wrapper());
>+    DEFAULT_REF_RETURN;
> }
> 
>-void Object::deref()
>+void Object::deref(DEREF_ARGUMENT_TYPE)
> {
>     CFRelease(wrapper());
> }
>diff --git a/Source/WebKit/Shared/ShareableResource.cpp b/Source/WebKit/Shared/ShareableResource.cpp
>index d147d80e574..b100d3b3753 100644
>--- a/Source/WebKit/Shared/ShareableResource.cpp
>+++ b/Source/WebKit/Shared/ShareableResource.cpp
>@@ -60,7 +60,7 @@ bool ShareableResource::Handle::decode(IPC::Decoder& decoder, Handle& handle)
> #if USE(CF)
> static void shareableResourceDeallocate(void *ptr, void *info)
> {
>-    static_cast<ShareableResource*>(info)->deref(); // Balanced by ref() in createShareableResourceDeallocator()
>+    static_cast<ShareableResource*>(info)->deref(DEREF_DEFAULT_ARGUMENTS); // Balanced by ref() in createShareableResourceDeallocator()
> }
>     
> static CFAllocatorRef createShareableResourceDeallocator(ShareableResource* resource)
>@@ -89,7 +89,7 @@ RefPtr<SharedBuffer> ShareableResource::wrapInSharedBuffer()
>     RetainPtr<CFDataRef> cfData = adoptCF(CFDataCreateWithBytesNoCopy(kCFAllocatorDefault, reinterpret_cast<const UInt8*>(data()), static_cast<CFIndex>(size()), deallocator.get()));
>     return SharedBuffer::create(cfData.get());
> #elif USE(SOUP)
>-    return SharedBuffer::wrapSoupBuffer(soup_buffer_new_with_owner(data(), size(), this, [](void* data) { static_cast<ShareableResource*>(data)->deref(); }));
>+    return SharedBuffer::wrapSoupBuffer(soup_buffer_new_with_owner(data(), size(), this, [](void* data) { static_cast<ShareableResource*>(data)->deref(DEREF_DEFAULT_ARGUMENTS); }));
> #else
>     ASSERT_NOT_REACHED();
>     return nullptr;
>diff --git a/Source/WebKit/Shared/cg/ShareableBitmapCG.cpp b/Source/WebKit/Shared/cg/ShareableBitmapCG.cpp
>index 41b2fea32b1..4e0456916f2 100644
>--- a/Source/WebKit/Shared/cg/ShareableBitmapCG.cpp
>+++ b/Source/WebKit/Shared/cg/ShareableBitmapCG.cpp
>@@ -137,14 +137,14 @@ void ShareableBitmap::releaseBitmapContextData(void* typelessBitmap, void* typel
> {
>     ShareableBitmap* bitmap = static_cast<ShareableBitmap*>(typelessBitmap);
>     ASSERT_UNUSED(typelessData, bitmap->data() == typelessData);
>-    bitmap->deref(); // Balanced by ref in createGraphicsContext.
>+    bitmap->deref(DEREF_DEFAULT_ARGUMENTS); // Balanced by ref in createGraphicsContext.
> }
> 
> void ShareableBitmap::releaseDataProviderData(void* typelessBitmap, const void* typelessData, size_t)
> {
>     ShareableBitmap* bitmap = static_cast<ShareableBitmap*>(typelessBitmap);
>     ASSERT_UNUSED(typelessData, bitmap->data() == typelessData);
>-    bitmap->deref(); // Balanced by ref in createCGImage.
>+    bitmap->deref(DEREF_DEFAULT_ARGUMENTS); // Balanced by ref in createCGImage.
> }
> 
> RefPtr<Image> ShareableBitmap::createImage()
>diff --git a/Source/WebKit/StorageProcess/IndexedDB/WebIDBConnectionToClient.h b/Source/WebKit/StorageProcess/IndexedDB/WebIDBConnectionToClient.h
>index 0087e8aa87c..b50dfbb3c01 100644
>--- a/Source/WebKit/StorageProcess/IndexedDB/WebIDBConnectionToClient.h
>+++ b/Source/WebKit/StorageProcess/IndexedDB/WebIDBConnectionToClient.h
>@@ -87,8 +87,8 @@ public:
> 
>     void didGetAllDatabaseNames(uint64_t callbackID, const Vector<String>& databaseNames) final;
> 
>-    void ref() override { RefCounted<WebIDBConnectionToClient>::ref(); }
>-    void deref() override { RefCounted<WebIDBConnectionToClient>::deref(); }
>+    REF_RETURN_TYPE ref() override { return RefCounted<WebIDBConnectionToClient>::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { RefCounted<WebIDBConnectionToClient>::deref(DEREF_ARGUMENT_NAME); }
> 
>     // Messages received from WebProcess
>     void deleteDatabase(const WebCore::IDBRequestData&);
>diff --git a/Source/WebKit/UIProcess/API/C/mac/WKContextPrivateMac.mm b/Source/WebKit/UIProcess/API/C/mac/WKContextPrivateMac.mm
>index 7f93c1e32aa..0eed0e7b3a8 100644
>--- a/Source/WebKit/UIProcess/API/C/mac/WKContextPrivateMac.mm
>+++ b/Source/WebKit/UIProcess/API/C/mac/WKContextPrivateMac.mm
>@@ -98,7 +98,7 @@ void WKContextGetInfoForInstalledPlugIns(WKContextRef contextRef, WKContextGetIn
>     dispatch_async(dispatch_get_main_queue(), ^() {
>         block(toAPI(array.get()), 0);
>     
>-        toImpl(contextRef)->deref();
>+        toImpl(contextRef)->deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> #endif
> }
>diff --git a/Source/WebKit/UIProcess/Launcher/mac/ProcessLauncherMac.mm b/Source/WebKit/UIProcess/Launcher/mac/ProcessLauncherMac.mm
>index 31105e4703c..fc299466c52 100644
>--- a/Source/WebKit/UIProcess/Launcher/mac/ProcessLauncherMac.mm
>+++ b/Source/WebKit/UIProcess/Launcher/mac/ProcessLauncherMac.mm
>@@ -270,7 +270,7 @@ void ProcessLauncher::launchProcess()
>             m_xpcConnection = nullptr;
>         }
> 
>-        deref();
>+        deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> }
> 
>diff --git a/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.cpp b/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.cpp
>index c85cc5a0465..6f0c67fead3 100644
>--- a/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.cpp
>+++ b/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.cpp
>@@ -79,14 +79,14 @@ void WebNotificationManagerProxy::processPoolDestroyed()
>     m_provider->removeNotificationManager(*this);
> }
> 
>-void WebNotificationManagerProxy::refWebContextSupplement()
>+REF_RETURN_TYPE WebNotificationManagerProxy::refWebContextSupplement()
> {
>-    API::Object::ref();
>+    return API::Object::ref();
> }
> 
>-void WebNotificationManagerProxy::derefWebContextSupplement()
>+void WebNotificationManagerProxy::derefWebContextSupplement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    API::Object::deref();
>+    API::Object::deref(DEREF_ARGUMENT_NAME);
> }
> 
> HashMap<String, bool> WebNotificationManagerProxy::notificationPermissions()
>diff --git a/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.h b/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.h
>index 542fbd9726e..ce2d4d4729d 100644
>--- a/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.h
>+++ b/Source/WebKit/UIProcess/Notifications/WebNotificationManagerProxy.h
>@@ -84,8 +84,8 @@ private:
> 
>     // WebContextSupplement
>     void processPoolDestroyed() override;
>-    void refWebContextSupplement() override;
>-    void derefWebContextSupplement() override;
>+    REF_RETURN_TYPE refWebContextSupplement() override;
>+    void derefWebContextSupplement(DEREF_ARGUMENT_TYPE) override;
> 
>     std::unique_ptr<API::NotificationProvider> m_provider;
>     // Pair comprised of web page ID and the web process's notification ID
>diff --git a/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.cpp b/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.cpp
>index b67cade25df..be23409b478 100644
>--- a/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.cpp
>+++ b/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.cpp
>@@ -335,14 +335,15 @@ void ResourceLoadStatisticsPersistentStorage::finishAllPendingWorkSynchronously(
>     semaphore.wait(WallTime::infinity());
> }
> 
>-void ResourceLoadStatisticsPersistentStorage::ref()
>+REF_RETURN_TYPE ResourceLoadStatisticsPersistentStorage::ref()
> {
>     m_memoryStore.ref();
>+    DEFAULT_REF_RETURN;
> }
> 
>-void ResourceLoadStatisticsPersistentStorage::deref()
>+void ResourceLoadStatisticsPersistentStorage::deref(DEREF_ARGUMENT_TYPE)
> {
>-    m_memoryStore.deref();
>+    m_memoryStore.deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> #if !PLATFORM(IOS)
>diff --git a/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.h b/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.h
>index b8d12f1717d..236aa574582 100644
>--- a/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.h
>+++ b/Source/WebKit/UIProcess/ResourceLoadStatisticsPersistentStorage.h
>@@ -50,8 +50,8 @@ public:
> 
>     void finishAllPendingWorkSynchronously();
> 
>-    void ref();
>-    void deref();
>+    REF_RETURN_TYPE ref();
>+    void deref(DEREF_ARGUMENT_TYPE);
> 
>     enum class ForceImmediateWrite {
>         No,
>diff --git a/Source/WebKit/UIProcess/WebContextSupplement.h b/Source/WebKit/UIProcess/WebContextSupplement.h
>index 80ca3a533a1..a3ccf48dcf2 100644
>--- a/Source/WebKit/UIProcess/WebContextSupplement.h
>+++ b/Source/WebKit/UIProcess/WebContextSupplement.h
>@@ -63,12 +63,12 @@ public:
>     WebProcessPool* processPool() const { return m_processPool; }
>     void clearProcessPool() { m_processPool = nullptr; }
> 
>-    void ref() { refWebContextSupplement(); }
>-    void deref() { derefWebContextSupplement(); }
>+    REF_RETURN_TYPE ref() { return refWebContextSupplement(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) { derefWebContextSupplement(DEREF_ARGUMENT_NAME); }
> 
> private:
>-    virtual void refWebContextSupplement() = 0;
>-    virtual void derefWebContextSupplement() = 0;
>+    virtual REF_RETURN_TYPE refWebContextSupplement() = 0;
>+    virtual void derefWebContextSupplement(DEREF_DECLARE_ARGUMENTS_WITH_DEFAULTS) = 0;
> 
>     WebProcessPool* m_processPool;
> };
>diff --git a/Source/WebKit/UIProcess/WebCookieManagerProxy.cpp b/Source/WebKit/UIProcess/WebCookieManagerProxy.cpp
>index af0e3ee2548..1d9e4f94b72 100644
>--- a/Source/WebKit/UIProcess/WebCookieManagerProxy.cpp
>+++ b/Source/WebKit/UIProcess/WebCookieManagerProxy.cpp
>@@ -97,14 +97,14 @@ void WebCookieManagerProxy::processDidClose(NetworkProcessProxy*)
>     m_callbacks.invalidate(CallbackBase::Error::ProcessExited);
> }
> 
>-void WebCookieManagerProxy::refWebContextSupplement()
>+REF_RETURN_TYPE WebCookieManagerProxy::refWebContextSupplement()
> {
>-    API::Object::ref();
>+    return API::Object::ref();
> }
> 
>-void WebCookieManagerProxy::derefWebContextSupplement()
>+void WebCookieManagerProxy::derefWebContextSupplement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    API::Object::deref();
>+    API::Object::deref(DEREF_ARGUMENT_NAME);
> }
> 
> void WebCookieManagerProxy::getHostnamesWithCookies(PAL::SessionID sessionID, Function<void (API::Array*, CallbackBase::Error)>&& callbackFunction)
>diff --git a/Source/WebKit/UIProcess/WebCookieManagerProxy.h b/Source/WebKit/UIProcess/WebCookieManagerProxy.h
>index 97f14add6df..ceb0c87b9af 100644
>--- a/Source/WebKit/UIProcess/WebCookieManagerProxy.h
>+++ b/Source/WebKit/UIProcess/WebCookieManagerProxy.h
>@@ -122,8 +122,8 @@ private:
>     void processPoolDestroyed() override;
>     void processDidClose(WebProcessProxy*) override;
>     void processDidClose(NetworkProcessProxy*) override;
>-    void refWebContextSupplement() override;
>-    void derefWebContextSupplement() override;
>+    REF_RETURN_TYPE refWebContextSupplement() override;
>+    void derefWebContextSupplement(DEREF_ARGUMENT_TYPE) override;
> 
>     // IPC::MessageReceiver
>     void didReceiveMessage(IPC::Connection&, IPC::Decoder&) override;
>diff --git a/Source/WebKit/UIProcess/WebGeolocationManagerProxy.cpp b/Source/WebKit/UIProcess/WebGeolocationManagerProxy.cpp
>index 52b011f5dba..883d90aae64 100644
>--- a/Source/WebKit/UIProcess/WebGeolocationManagerProxy.cpp
>+++ b/Source/WebKit/UIProcess/WebGeolocationManagerProxy.cpp
>@@ -76,14 +76,14 @@ void WebGeolocationManagerProxy::processDidClose(WebProcessProxy* webProcessProx
>     removeRequester(webProcessProxy);
> }
> 
>-void WebGeolocationManagerProxy::refWebContextSupplement()
>+REF_RETURN_TYPE WebGeolocationManagerProxy::refWebContextSupplement()
> {
>-    API::Object::ref();
>+    return API::Object::ref();
> }
> 
>-void WebGeolocationManagerProxy::derefWebContextSupplement()
>+void WebGeolocationManagerProxy::derefWebContextSupplement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    API::Object::deref();
>+    API::Object::deref(DEREF_ARGUMENT_NAME);
> }
> 
> void WebGeolocationManagerProxy::providerDidChangePosition(WebGeolocationPosition* position)
>diff --git a/Source/WebKit/UIProcess/WebGeolocationManagerProxy.h b/Source/WebKit/UIProcess/WebGeolocationManagerProxy.h
>index 15153920730..1f61d785b10 100644
>--- a/Source/WebKit/UIProcess/WebGeolocationManagerProxy.h
>+++ b/Source/WebKit/UIProcess/WebGeolocationManagerProxy.h
>@@ -64,8 +64,8 @@ private:
>     // WebContextSupplement
>     void processPoolDestroyed() override;
>     void processDidClose(WebProcessProxy*) override;
>-    void refWebContextSupplement() override;
>-    void derefWebContextSupplement() override;
>+    REF_RETURN_TYPE refWebContextSupplement() override;
>+    void derefWebContextSupplement(DEREF_ARGUMENT_TYPE) override;
> 
>     // IPC::MessageReceiver
>     void didReceiveMessage(IPC::Connection&, IPC::Decoder&) override;
>diff --git a/Source/WebKit/UIProcess/WebMediaSessionFocusManager.cpp b/Source/WebKit/UIProcess/WebMediaSessionFocusManager.cpp
>index 2cdcd176529..17df05d256c 100644
>--- a/Source/WebKit/UIProcess/WebMediaSessionFocusManager.cpp
>+++ b/Source/WebKit/UIProcess/WebMediaSessionFocusManager.cpp
>@@ -47,14 +47,14 @@ WebMediaSessionFocusManager::WebMediaSessionFocusManager(WebProcessPool* process
> 
> // WebContextSupplement
> 
>-void WebMediaSessionFocusManager::refWebContextSupplement()
>+REF_RETURN_TYPE WebMediaSessionFocusManager::refWebContextSupplement()
> {
>-    API::Object::ref();
>+    return API::Object::ref();
> }
> 
>-void WebMediaSessionFocusManager::derefWebContextSupplement()
>+void WebMediaSessionFocusManager::derefWebContextSupplement(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME)
> {
>-    API::Object::deref();
>+    API::Object::deref(DEREF_ARGUMENT_NAME);
> }
> 
> void WebMediaSessionFocusManager::initializeClient(const WKMediaSessionFocusManagerClientBase* client)
>diff --git a/Source/WebKit/UIProcess/WebMediaSessionFocusManager.h b/Source/WebKit/UIProcess/WebMediaSessionFocusManager.h
>index 24c7037df6a..8aa3e09f463 100644
>--- a/Source/WebKit/UIProcess/WebMediaSessionFocusManager.h
>+++ b/Source/WebKit/UIProcess/WebMediaSessionFocusManager.h
>@@ -58,8 +58,8 @@ private:
>     explicit WebMediaSessionFocusManager(WebProcessPool*);
> 
>     // WebContextSupplement
>-    void refWebContextSupplement() override;
>-    void derefWebContextSupplement() override;
>+    REF_RETURN_TYPE refWebContextSupplement() override;
>+    void derefWebContextSupplement(DEREF_ARGUMENT_TYPE) override;
> 
>     void updatePlaybackAttribute(WKMediaSessionFocusManagerPlaybackAttribute, bool);
> 
>diff --git a/Source/WebKit/WebProcess/Databases/IndexedDB/WebIDBConnectionToServer.h b/Source/WebKit/WebProcess/Databases/IndexedDB/WebIDBConnectionToServer.h
>index 28c9889900d..856dcaef9b0 100644
>--- a/Source/WebKit/WebProcess/Databases/IndexedDB/WebIDBConnectionToServer.h
>+++ b/Source/WebKit/WebProcess/Databases/IndexedDB/WebIDBConnectionToServer.h
>@@ -76,8 +76,8 @@ public:
> 
>     void getAllDatabaseNames(const WebCore::SecurityOriginData& topOrigin, const WebCore::SecurityOriginData& openingOrigin, uint64_t callbackID) final;
> 
>-    void ref() override { RefCounted<WebIDBConnectionToServer>::ref(); }
>-    void deref() override { RefCounted<WebIDBConnectionToServer>::deref(); }
>+    REF_RETURN_TYPE ref() override { return RefCounted<WebIDBConnectionToServer>::ref(); }
>+    void deref(DEREF_ARGUMENT_TYPE DEREF_ARGUMENT_NAME) override { RefCounted<WebIDBConnectionToServer>::deref(DEREF_ARGUMENT_NAME); }
> 
>     // Messages received from StorageProcess
>     void didDeleteDatabase(const WebCore::IDBResultData&);
>diff --git a/Source/WebKit/WebProcess/InjectedBundle/InjectedBundle.cpp b/Source/WebKit/WebProcess/InjectedBundle/InjectedBundle.cpp
>index f842b8426f9..44599752495 100644
>--- a/Source/WebKit/WebProcess/InjectedBundle/InjectedBundle.cpp
>+++ b/Source/WebKit/WebProcess/InjectedBundle/InjectedBundle.cpp
>@@ -610,8 +610,10 @@ Vector<String> InjectedBundle::liveDocumentURLs()
> {
>     Vector<String> result;
>     
>-    for (const auto* document : Document::allDocuments())
>+    for (const auto* document : Document::allDocuments()) {
>+        WTFLogAlways("InjectedBundle::liveDocumentURLs: document %p (refcount %d) %s", document, document->refCount(), document->url().string().utf8().data());
>         result.append(document->url().string());
>+    }
> 
>     return result;
> }
>diff --git a/Source/WebKit/WebProcess/InjectedBundle/InjectedBundlePageLoaderClient.cpp b/Source/WebKit/WebProcess/InjectedBundle/InjectedBundlePageLoaderClient.cpp
>index e41e8318099..aa82cd55e6c 100644
>--- a/Source/WebKit/WebProcess/InjectedBundle/InjectedBundlePageLoaderClient.cpp
>+++ b/Source/WebKit/WebProcess/InjectedBundle/InjectedBundlePageLoaderClient.cpp
>@@ -62,7 +62,7 @@ void InjectedBundlePageLoaderClient::willLoadURLRequest(WebPage& page, const Res
> static void releaseSharedBuffer(unsigned char*, const void* data)
> {
>     // Balanced by ref() in InjectedBundlePageLoaderClient::willLoadDataRequest().
>-    static_cast<SharedBuffer*>(const_cast<void*>(data))->deref();
>+    static_cast<SharedBuffer*>(const_cast<void*>(data))->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void InjectedBundlePageLoaderClient::willLoadDataRequest(WebPage& page, const ResourceRequest& request, SharedBuffer* sharedBuffer, const String& MIMEType, const String& encodingName, const URL& unreachableURL, API::Object* userData)
>diff --git a/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm b/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>index c1ac4d58e4f..a711e516715 100644
>--- a/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>+++ b/Source/WebKit/WebProcess/Plugins/PDF/PDFPlugin.mm
>@@ -941,7 +941,7 @@ static void jsPDFDocInitialize(JSContextRef ctx, JSObjectRef object)
> static void jsPDFDocFinalize(JSObjectRef object)
> {
>     PDFPlugin* pdfView = static_cast<PDFPlugin*>(JSObjectGetPrivate(object));
>-    pdfView->deref();
>+    pdfView->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> JSValueRef PDFPlugin::jsPDFDocPrint(JSContextRef ctx, JSObjectRef function, JSObjectRef thisObject, size_t argumentCount, const JSValueRef arguments[], JSValueRef* exception)
>diff --git a/Source/WebKit/WebProcess/Plugins/PluginView.cpp b/Source/WebKit/WebProcess/Plugins/PluginView.cpp
>index 90e0109e966..a2af8472260 100644
>--- a/Source/WebKit/WebProcess/Plugins/PluginView.cpp
>+++ b/Source/WebKit/WebProcess/Plugins/PluginView.cpp
>@@ -1654,7 +1654,7 @@ void PluginView::unprotectPluginFromDestruction()
>         return;
>     }
> 
>-    deref();
>+    deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> void PluginView::didFinishLoad(WebFrame* webFrame)
>diff --git a/Source/WebKit/WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp b/Source/WebKit/WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp
>index e9fc74da4eb..dba0dd9d0a7 100644
>--- a/Source/WebKit/WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp
>+++ b/Source/WebKit/WebProcess/WebCoreSupport/WebFrameLoaderClient.cpp
>@@ -137,7 +137,7 @@ void WebFrameLoaderClient::frameLoaderDestroyed()
>     m_frame->invalidate();
> 
>     // Balances explicit ref() in WebFrame::create().
>-    m_frame->deref();
>+    m_frame->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> bool WebFrameLoaderClient::hasHTMLView() const
>diff --git a/Source/WebKit/WebProcess/WebPage/mac/TiledCoreAnimationDrawingArea.mm b/Source/WebKit/WebProcess/WebPage/mac/TiledCoreAnimationDrawingArea.mm
>index d02ed721a7b..3114da746ed 100644
>--- a/Source/WebKit/WebProcess/WebPage/mac/TiledCoreAnimationDrawingArea.mm
>+++ b/Source/WebKit/WebProcess/WebPage/mac/TiledCoreAnimationDrawingArea.mm
>@@ -392,7 +392,7 @@ void TiledCoreAnimationDrawingArea::dispatchAfterEnsuringUpdatedScrollPosition(W
>         if (!m_layerTreeStateIsFrozen)
>             m_layerFlushScheduler.resume();
> 
>-        webPage->deref();
>+        webPage->deref(DEREF_DEFAULT_ARGUMENTS);
>     });
> #else
>     function();
>diff --git a/Source/WebKitLegacy/ios/WebCoreSupport/WebGeolocation.mm b/Source/WebKitLegacy/ios/WebCoreSupport/WebGeolocation.mm
>index dac61c1f5d4..83fa610002e 100644
>--- a/Source/WebKitLegacy/ios/WebCoreSupport/WebGeolocation.mm
>+++ b/Source/WebKitLegacy/ios/WebCoreSupport/WebGeolocation.mm
>@@ -56,7 +56,7 @@ - (void)setIsAllowed:(BOOL)allowed
> - (void)dealloc
> {
>     if (_private)
>-        reinterpret_cast<Geolocation*>(_private)->deref();
>+        reinterpret_cast<Geolocation*>(_private)->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOM.mm b/Source/WebKitLegacy/mac/DOM/DOM.mm
>index 83d56d04486..6074c1e3182 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOM.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOM.mm
>@@ -839,14 +839,14 @@ @implementation DOMNodeFilter
> - (void)dealloc
> {
>     if (_internal)
>-        reinterpret_cast<WebCore::NodeFilter*>(_internal)->deref();
>+        reinterpret_cast<WebCore::NodeFilter*>(_internal)->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
> - (void)finalize
> {
>     if (_internal)
>-        reinterpret_cast<WebCore::NodeFilter*>(_internal)->deref();
>+        reinterpret_cast<WebCore::NodeFilter*>(_internal)->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super finalize];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMBlob.mm b/Source/WebKitLegacy/mac/DOM/DOMBlob.mm
>index 75914db9672..c5d051efcc7 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMBlob.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMBlob.mm
>@@ -46,7 +46,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMCSSRule.mm b/Source/WebKitLegacy/mac/DOM/DOMCSSRule.mm
>index 760fb5b1885..cacb51a0fa6 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMCSSRule.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMCSSRule.mm
>@@ -49,7 +49,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMCSSRuleList.mm b/Source/WebKitLegacy/mac/DOM/DOMCSSRuleList.mm
>index 3cac5c2ce81..9bedbc8bcd2 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMCSSRuleList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMCSSRuleList.mm
>@@ -48,7 +48,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMCSSStyleDeclaration.mm b/Source/WebKitLegacy/mac/DOM/DOMCSSStyleDeclaration.mm
>index 0a0677df6a1..9ec710cee70 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMCSSStyleDeclaration.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMCSSStyleDeclaration.mm
>@@ -51,7 +51,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMCSSValue.mm b/Source/WebKitLegacy/mac/DOM/DOMCSSValue.mm
>index 799fb619a2a..890a120297f 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMCSSValue.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMCSSValue.mm
>@@ -46,7 +46,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMCounter.mm b/Source/WebKitLegacy/mac/DOM/DOMCounter.mm
>index b0e4af42e2d..a4511ada197 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMCounter.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMCounter.mm
>@@ -46,7 +46,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMEvent.mm b/Source/WebKitLegacy/mac/DOM/DOMEvent.mm
>index 9aca41b65fa..62d1aee280b 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMEvent.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMEvent.mm
>@@ -48,7 +48,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMFileList.mm b/Source/WebKitLegacy/mac/DOM/DOMFileList.mm
>index a2674fe7f90..056e149fcee 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMFileList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMFileList.mm
>@@ -47,7 +47,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMHTMLCollection.mm b/Source/WebKitLegacy/mac/DOM/DOMHTMLCollection.mm
>index 7fe73819bdd..f0c7ded158d 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMHTMLCollection.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMHTMLCollection.mm
>@@ -50,7 +50,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMHTMLOptionsCollection.mm b/Source/WebKitLegacy/mac/DOM/DOMHTMLOptionsCollection.mm
>index fdfa6e8fc33..f0a127e4785 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMHTMLOptionsCollection.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMHTMLOptionsCollection.mm
>@@ -51,7 +51,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMImplementation.mm b/Source/WebKitLegacy/mac/DOM/DOMImplementation.mm
>index 7442ea9ade0..2475aa3f479 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMImplementation.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMImplementation.mm
>@@ -53,7 +53,7 @@ - (void)dealloc
>     if (WebCoreObjCScheduleDeallocateOnMainThread([DOMImplementation class], self))
>         return;
>     if (_internal)
>-        unwrap(*self).deref();
>+        unwrap(*self).deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMMediaError.mm b/Source/WebKitLegacy/mac/DOM/DOMMediaError.mm
>index 139556c55aa..6ffa625ed62 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMMediaError.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMMediaError.mm
>@@ -51,7 +51,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMMediaList.mm b/Source/WebKitLegacy/mac/DOM/DOMMediaList.mm
>index 2df34205b6b..eede6d2ef82 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMMediaList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMMediaList.mm
>@@ -48,7 +48,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMNamedNodeMap.mm b/Source/WebKitLegacy/mac/DOM/DOMNamedNodeMap.mm
>index 5dd39564dd4..433410145bd 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMNamedNodeMap.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMNamedNodeMap.mm
>@@ -47,7 +47,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMNode.mm b/Source/WebKitLegacy/mac/DOM/DOMNode.mm
>index ec130f4f463..07c552e0ca6 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMNode.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMNode.mm
>@@ -78,7 +78,7 @@ - (void)dealloc
>     if (WebCoreObjCScheduleDeallocateOnMainThread([DOMNode class], self))
>         return;
>     if (_internal)
>-        unwrap(*self).deref();
>+        unwrap(*self).deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMNodeIterator.mm b/Source/WebKitLegacy/mac/DOM/DOMNodeIterator.mm
>index 6cb2b242e68..1973d154074 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMNodeIterator.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMNodeIterator.mm
>@@ -51,7 +51,7 @@ - (void)dealloc
> 
>     if (_internal) {
>         [self detach];
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     };
>     [super dealloc];
> }
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMNodeList.mm b/Source/WebKitLegacy/mac/DOM/DOMNodeList.mm
>index 1bbf01bf794..6fef2591bff 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMNodeList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMNodeList.mm
>@@ -46,7 +46,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMRGBColor.mm b/Source/WebKitLegacy/mac/DOM/DOMRGBColor.mm
>index 8ab7a52e874..48a198883c9 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMRGBColor.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMRGBColor.mm
>@@ -53,7 +53,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMRange.mm b/Source/WebKitLegacy/mac/DOM/DOMRange.mm
>index 24f85f71f6e..86d28d3446c 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMRange.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMRange.mm
>@@ -49,7 +49,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMRect.mm b/Source/WebKitLegacy/mac/DOM/DOMRect.mm
>index 58bbcd57664..fa13d9e40f9 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMRect.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMRect.mm
>@@ -47,7 +47,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMStyleSheet.mm b/Source/WebKitLegacy/mac/DOM/DOMStyleSheet.mm
>index 526ad97ec03..3c676b05e55 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMStyleSheet.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMStyleSheet.mm
>@@ -51,7 +51,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMStyleSheetList.mm b/Source/WebKitLegacy/mac/DOM/DOMStyleSheetList.mm
>index a0539a6e85d..2923242594f 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMStyleSheetList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMStyleSheetList.mm
>@@ -49,7 +49,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMTimeRanges.mm b/Source/WebKitLegacy/mac/DOM/DOMTimeRanges.mm
>index f0836202dcb..6dea7d44da9 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMTimeRanges.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMTimeRanges.mm
>@@ -50,7 +50,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMTokenList.mm b/Source/WebKitLegacy/mac/DOM/DOMTokenList.mm
>index a7196c6d023..0f41abd5ff8 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMTokenList.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMTokenList.mm
>@@ -47,7 +47,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMTreeWalker.mm b/Source/WebKitLegacy/mac/DOM/DOMTreeWalker.mm
>index de0419fe9d1..f25a9b203c9 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMTreeWalker.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMTreeWalker.mm
>@@ -48,7 +48,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMXPath.mm b/Source/WebKitLegacy/mac/DOM/DOMXPath.mm
>index 53dc22de1ea..0cc5f0b9b6f 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMXPath.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMXPath.mm
>@@ -41,14 +41,14 @@ @implementation DOMNativeXPathNSResolver
> - (void)dealloc
> {
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
> - (void)finalize
> {
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super finalize];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMXPathExpression.mm b/Source/WebKitLegacy/mac/DOM/DOMXPathExpression.mm
>index 0e0e0695763..e2de5befe3b 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMXPathExpression.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMXPathExpression.mm
>@@ -48,7 +48,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/DOM/DOMXPathResult.mm b/Source/WebKitLegacy/mac/DOM/DOMXPathResult.mm
>index 9e21ffc81ad..a4929493da8 100644
>--- a/Source/WebKitLegacy/mac/DOM/DOMXPathResult.mm
>+++ b/Source/WebKitLegacy/mac/DOM/DOMXPathResult.mm
>@@ -47,7 +47,7 @@ - (void)dealloc
>         return;
> 
>     if (_internal)
>-        IMPL->deref();
>+        IMPL->deref(DEREF_DEFAULT_ARGUMENTS);
>     [super dealloc];
> }
> 
>diff --git a/Source/WebKitLegacy/mac/History/WebBackForwardList.mm b/Source/WebKitLegacy/mac/History/WebBackForwardList.mm
>index 78e30f9fbe0..0260acfa4ee 100644
>--- a/Source/WebKitLegacy/mac/History/WebBackForwardList.mm
>+++ b/Source/WebKitLegacy/mac/History/WebBackForwardList.mm
>@@ -120,7 +120,7 @@ - (void)dealloc
>     if (backForwardList) {
>         ASSERT(backForwardList->closed());
>         backForwardLists().remove(backForwardList);
>-        backForwardList->deref();
>+        backForwardList->deref(DEREF_DEFAULT_ARGUMENTS);
>     }
> 
>     [super dealloc];
>diff --git a/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm b/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>index 4e4c13dfb73..c3c12515472 100644
>--- a/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>+++ b/Source/WebKitLegacy/mac/WebCoreSupport/WebSecurityOrigin.mm
>@@ -104,7 +104,7 @@ - (BOOL)isEqual:(id)anObject
> - (void)dealloc
> {
>     if (_private)
>-        reinterpret_cast<SecurityOrigin*>(_private)->deref();
>+        reinterpret_cast<SecurityOrigin*>(_private)->deref(DEREF_DEFAULT_ARGUMENTS);
>     if (_applicationCacheQuotaManager)
>         [(NSObject *)_applicationCacheQuotaManager release];
>     if (_databaseQuotaManager)
>diff --git a/Tools/DumpRenderTree/TestRunner.cpp b/Tools/DumpRenderTree/TestRunner.cpp
>index f8ad9515174..9a39781cdfb 100644
>--- a/Tools/DumpRenderTree/TestRunner.cpp
>+++ b/Tools/DumpRenderTree/TestRunner.cpp
>@@ -2051,7 +2051,7 @@ static JSValueRef runUIScriptCallback(JSContextRef context, JSObjectRef, JSObjec
> static void testRunnerObjectFinalize(JSObjectRef object)
> {
>     TestRunner* controller = static_cast<TestRunner*>(JSObjectGetPrivate(object));
>-    controller->deref();
>+    controller->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> // Object Creation
>diff --git a/Tools/DumpRenderTree/mac/DumpRenderTree.mm b/Tools/DumpRenderTree/mac/DumpRenderTree.mm
>index 1f7202f78c4..f4d06e81a99 100644
>--- a/Tools/DumpRenderTree/mac/DumpRenderTree.mm
>+++ b/Tools/DumpRenderTree/mac/DumpRenderTree.mm
>@@ -1228,6 +1228,10 @@ static void dumpLiveDocuments()
>     WTFLogAlways("%u live documents:", WebCore::Document::allDocuments().size());
>     for (const auto* document : WebCore::Document::allDocuments()) {
>         WTFLogAlways("Document %p (refCount %d, referencingNodeCount %u) %s", document, document->refCount(), document->referencingNodeCount(), document->url().string().utf8().data());
>+
>+        WTFLogAlways("Document %p reference stacks:\n");
>+        document->refTracker().dumpRemainingReferences();
>+        WTFLogAlways("\n");
>     }
> }
> 
>diff --git a/Tools/TestRunnerShared/Bindings/JSWrapper.cpp b/Tools/TestRunnerShared/Bindings/JSWrapper.cpp
>index 6f47c1062ee..fa45af5a30c 100644
>--- a/Tools/TestRunnerShared/Bindings/JSWrapper.cpp
>+++ b/Tools/TestRunnerShared/Bindings/JSWrapper.cpp
>@@ -74,7 +74,7 @@ void JSWrapper::finalize(JSObjectRef object)
>     JSWrappable* wrappable = unwrapObject(object);
>     if (!wrappable)
>         return;
>-    wrappable->deref();
>+    wrappable->deref(DEREF_DEFAULT_ARGUMENTS);
> }
> 
> } // namespace WTR

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Attachments on bug 186269: 341904 | 348580 | 348584 | 348586 | 348588 | 348589 | 348592 | 348595 | 348596 | 348605 | 348606 | 348608 | 348610 | 348613 | 348614 | 348632 | 348640