Move Frame to the Oilpan heap.

Source/core/frame/FrameDestructionObserver.h

 /*
  * Copyright (C) 2011 Google, Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
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  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
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  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY GOOGLE 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,
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 #ifndef FrameDestructionObserver_h
 #define FrameDestructionObserver_h
 
+#include "platform/heap/Handle.h"
+
 namespace blink {
 
 class LocalFrame;
 
-class FrameDestructionObserver {
+class FrameDestructionObserver : public WillBeGarbageCollectedMixin {
 public:
     explicit FrameDestructionObserver(LocalFrame*);
 
+#if !ENABLE(OILPAN)
+    // Oilpan: Frame finalization can now only be observed via
+    // a weak callback -- deriving objects should register such
+    // a weak callback if they need to catch when that happens.
     virtual void frameDestroyed();
+#endif
     virtual void willDetachFrameHost();
 
     LocalFrame* frame() const { return m_frame; }
 
+    virtual void trace(Visitor*);
+
 protected:
+#if !ENABLE(OILPAN)
     virtual ~FrameDestructionObserver();
+#endif
     void observeFrame(LocalFrame*);
 
-    LocalFrame* m_frame;
+    RawPtrWillBeWeakMember<LocalFrame> m_frame;
 };
 
 }
 
 #endif