ChangeLog

2012-08-01  Ulan Degenbaev  <ulan@chromium.org>

        [chromium] Improve garbage collector hint if page uses Canvas contexts

        https://bugs.webkit.org/show_bug.cgi?id=92856

        Reviewed by NOBODY (OOPS!).

        Request GC by sending context disposed and idle notification to V8 instead

        of sending low memory notification. It is faster as it causes one GC

        instead of seven GCs caused by low memory notification.

        * bindings/v8/V8Binding.cpp:

        (WebCore::V8BindingPerIsolateData::V8BindingPerIsolateData):

        * bindings/v8/V8Binding.h:

        (V8BindingPerIsolateData):

        (WebCore::V8BindingPerIsolateData::setGarbageCollectionHint):

        (WebCore::V8BindingPerIsolateData::clearGarbageCollectionHint):

        (WebCore::V8BindingPerIsolateData::isGarbageCollectionHint):

        * bindings/v8/V8Proxy.cpp:

        (WebCore::V8Proxy::hintForGCIfNecessary):

        * bindings/v8/custom/V8HTMLCanvasElementCustom.cpp:

        (WebCore::V8HTMLCanvasElement::getContextCallback):

2012-07-31  Raul Hudea  <rhudea@adobe.com>

        Inspector crashes when trying to inspect a page with CSS region styling

Source/WebCore/bindings/v8/V8Binding.cpp

@@V8BindingPerIsolateData::V8BindingPerIsolateData(v8::Isolate* isolate)

#ifndef NDEBUG

    , m_internalScriptRecursionLevel(0)

#endif

63 , m_~~lowMemoryNotifi~~cationHint(false)

63 , m_garbageCollectionHint(false)

{

}

Source/WebCore/bindings/v8/V8Binding.h

@@namespace WebCore {

        void reportMemoryUsage(MemoryObjectInfo*) const;

        // Gives the system a hint that we should send a low memory

        // notification upon the next close or navigation event,

        // because some expensive objects have been allocated that we

        // want to take every opportunity to collect.

        void setLowMemoryNotificationHint() { m_lowMemoryNotificationHint = true; }

        void clearLowMemoryNotificationHint() { m_lowMemoryNotificationHint = false; }

        bool isLowMemoryNotificationHint() const { return m_lowMemoryNotificationHint; }

        // Gives the system a hint that we should request garbage collection

        // upon the next close or navigation event, because some expensive

        // objects have been allocated that we want to take every opportunity

        // to collect.

        void setGarbageCollectionHint() { m_garbageCollectionHint = true; }

        void clearGarbageCollectionHint() { m_garbageCollectionHint = false; }

        bool isGarbageCollectionHint() const { return m_garbageCollectionHint; }

    private:

        explicit V8BindingPerIsolateData(v8::Isolate*);

@@namespace WebCore {

#endif

        GCEventData m_gcEventData;

260 bool m_~~lowMemoryNotifi~~cationHint;

260 bool m_garbageCollectionHint;

    };

    class ConstructorMode {

Source/WebCore/bindings/v8/V8Proxy.cpp

@@void V8Proxy::resetIsolatedWorlds()

void V8Proxy::hintForGCIfNecessary()

{

    V8BindingPerIsolateData* data = V8BindingPerIsolateData::current();

    if (data->isLowMemoryNotificationHint()) {

        data->clearLowMemoryNotificationHint();

        v8::V8::LowMemoryNotification();

    if (data->isGarbageCollectionHint()) {

        const int longIdlePauseInMs = 1000;

        data->clearGarbageCollectionHint();

        v8::V8::ContextDisposedNotification();

        v8::V8::IdleNotification(longIdlePauseInMs);

    }

}

Source/WebCore/bindings/v8/custom/V8HTMLCanvasElementCustom.cpp

@@v8::Handle<v8::Value> V8HTMLCanvasElement::getContextCallback(const v8::Argument

    // want to take an opportunity to get rid of them as soon as possible when we

    // navigate away from pages using them.

    V8BindingPerIsolateData* perIsolateData = V8BindingPerIsolateData::current(args.GetIsolate());

94 perIsolateData->setL~~owMemoryNotifi~~cationHint();

94 perIsolateData->setGarbageCollectionHint();

    if (result->is2d())

        return toV8(static_cast<CanvasRenderingContext2D*>(result), args.GetIsolate());