[WPE][GTK] Enable process swap on navigation to new origin

• Component: WebKitGTK
• Status: RESOLVED FIXED

[Michael Catanzaro]

We should probably enable process swap on navigation to new origin for WPE/GTK. (...right?)

Hey Brady, could you help us understand:

 * Is there any reason we would NOT want to do this unconditionally? (It doesn't seem like something to expose public GTK/WPE API for.)
 * This is important because it's required for site isolation slash Spectre mitigation... right?

[Michael Catanzaro]

Patch is trivial:

diff --git a/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp b/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
index b52591d625e..829734126bc 100644
--- a/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
+++ b/Source/WebKit/UIProcess/API/glib/WebKitWebContext.cpp
@@ -335,6 +335,7 @@ static void webkitWebContextConstructed(GObject* object)
     configuration.setInjectedBundlePath(WebCore::FileSystem::stringFromFileSystemRepresentation(bundleFilename.get()));
     configuration.setMaximumProcessCount(1);
     configuration.setDiskCacheSpeculativeValidationEnabled(true);
+    configuration.setProcessSwapsOnNavigation(true);
 
     WebKitWebContext* webContext = WEBKIT_WEB_CONTEXT(object);
     WebKitWebContextPrivate* priv = webContext->priv;

I tested this out and it sort of works. The navigation swap seems to occur as expected. However, back/forward list is broken: trying to navigate back past a process swap does not work properly.

[Chris Dumez]

It is not enabled by default for COCOA yet. We are still working on layout test failures and then we'll have to work on performance. There is a cost to launching new processes (launch time and losing caches for e.g.).

[Michael Catanzaro]

OK, let's definitely delay until you think it's ready for Cocoa.

[Michael Catanzaro]

Enabled in r246148.