Support "await a stable state" and "provide a stable state"

Source/web/WebKit.cpp

 /*
  * Copyright (C) 2009 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 21 matching lines @@
 #include "WebKit.h"
 
 #include "IDBFactoryBackendProxy.h"
 #include "RuntimeEnabledFeatures.h"
 #include "WebMediaPlayerClientImpl.h"
 #include "bindings/v8/V8Binding.h"
 #include "bindings/v8/V8Initializer.h"
 #include "bindings/v8/V8RecursionScope.h"
 #include "core/Init.h"
 #include "core/dom/Microtask.h"
+#include "core/frame/Settings.h"
+#include "core/html/StableState.h"
 #include "core/page/Page.h"
-#include "core/frame/Settings.h"
 #include "core/workers/WorkerGlobalScopeProxy.h"
 #include "heap/Heap.h"
 #include "heap/glue/MessageLoopInterruptor.h"
 #include "heap/glue/PendingGCRunner.h"
 #include "platform/LayoutTestSupport.h"
 #include "platform/Logging.h"
 #include "platform/graphics/ImageDecodingStore.h"
 #include "platform/graphics/media/MediaPlayer.h"
 #include "public/platform/Platform.h"
 #include "public/platform/WebPrerenderingSupport.h"
 #include "public/platform/WebThread.h"
 #include "wtf/Assertions.h"
 #include "wtf/CryptographicallyRandomNumber.h"
 #include "wtf/MainThread.h"
 #include "wtf/WTF.h"
 #include "wtf/text/AtomicString.h"
 #include "wtf/text/TextEncoding.h"
 #include <v8.h>
 
 namespace blink {
 
 namespace {
 
 class EndOfTaskRunner : public WebThread::TaskObserver {
 public:
     virtual void willProcessTask() { }
     virtual void didProcessTask()
     {
         WebCore::Microtask::performCheckpoint();
+        WebCore::StableState::provide();
     }
 };
 
 } // namespace
 
 static WebThread::TaskObserver* s_endOfTaskRunner = 0;
 static WebThread::TaskObserver* s_pendingGCRunner = 0;
 static WebCore::ThreadState::Interruptor* s_messageLoopInterruptor = 0;
 static WebCore::ThreadState::Interruptor* s_isolateInterruptor = 0;
 
@@ skipping 166 matching lines @@
         channel->state = WTFLogChannelOn;
 #endif // !LOG_DISABLED
 }
 
 void resetPluginCache(bool reloadPages)
 {
     WebCore::Page::refreshPlugins(reloadPages);
 }
 
 } // namespace blink