Move MainThreadTaskRunner off Oilpan heap to simplify posting.

third_party/WebKit/Source/core/dom/MainThreadTaskRunner.h

 /*
  * Copyright (C) 2013 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.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 15 matching lines @@
 
 #ifndef MainThreadTaskRunner_h
 #define MainThreadTaskRunner_h
 
 #include "core/CoreExport.h"
 #include "platform/Timer.h"
 #include "platform/heap/Handle.h"
 #include "wtf/Allocator.h"
 #include "wtf/Noncopyable.h"
 #include "wtf/Vector.h"
+#include "wtf/WeakPtr.h"
 
 namespace blink {
 
 class ExecutionContext;
 class ExecutionContextTask;
 
-class CORE_EXPORT MainThreadTaskRunner final : public GarbageCollectedFinalized<MainThreadTaskRunner> {
+class CORE_EXPORT MainThreadTaskRunner final {
+    USING_FAST_MALLOC(MainThreadTaskRunner);
     WTF_MAKE_NONCOPYABLE(MainThreadTaskRunner);
 public:
-    static MainThreadTaskRunner* create(ExecutionContext*);
+    static PassOwnPtr<MainThreadTaskRunner> create(ExecutionContext*);
 
     ~MainThreadTaskRunner();
 
     DECLARE_TRACE();
 
     void postTask(const WebTraceLocation&, std::unique_ptr<ExecutionContextTask>); // Executes the task on context's thread asynchronously.
     void postInspectorTask(const WebTraceLocation&, std::unique_ptr<ExecutionContextTask>);
     void perform(std::unique_ptr<ExecutionContextTask>, bool);
 
     void suspend();
     void resume();
 
 private:
     explicit MainThreadTaskRunner(ExecutionContext*);
 
     void pendingTasksTimerFired(Timer<MainThreadTaskRunner>*);
 
     void postTaskInternal(const WebTraceLocation&, std::unique_ptr<ExecutionContextTask>, bool isInspectorTask);
 
-    Member<ExecutionContext> m_context;
+    // Untraced back reference to the owner Document;
+    // this object has identical lifetime to it.
+    UntracedMember<ExecutionContext> m_context;
     Timer<MainThreadTaskRunner> m_pendingTasksTimer;
     Vector<std::unique_ptr<ExecutionContextTask>> m_pendingTasks;
     bool m_suspended;
+    WeakPtrFactory<MainThreadTaskRunner> m_weakFactory;
 };
 
-inline MainThreadTaskRunner* MainThreadTaskRunner::create(ExecutionContext* context)
+inline PassOwnPtr<MainThreadTaskRunner> MainThreadTaskRunner::create(ExecutionContext* context)
 {
-    return new MainThreadTaskRunner(context);
+    return adoptPtr(new MainThreadTaskRunner(context));
 }
 
 } // namespace blink
 
 #endif