Oilpan: make DOMWindowProperty a GC mixin.

Source/core/frame/Console.h

 /*
  * Copyright (C) 2007 Apple 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 27 matching lines @@
 
 namespace blink {
 
 class LocalFrame;
 class MemoryInfo;
 class Page;
 class ScriptArguments;
 
 class Console FINAL : public ConsoleBase, public DOMWindowProperty {
     DEFINE_WRAPPERTYPEINFO();
+    WILL_BE_USING_GARBAGE_COLLECTED_MIXIN(Console);
 public:
     static PassRefPtrWillBeRawPtr<Console> create(LocalFrame* frame)
     {
         return adoptRefWillBeNoop(new Console(frame));
     }
     virtual ~Console();
 
     PassRefPtrWillBeRawPtr<MemoryInfo> memory() const;
 
-    virtual void trace(Visitor* visitor) OVERRIDE { ConsoleBase::trace(visitor); }
+    virtual void trace(Visitor*) OVERRIDE;
 
 protected:
     virtual ExecutionContext* context() OVERRIDE;
     virtual void reportMessageToConsole(PassRefPtrWillBeRawPtr<ConsoleMessage>) OVERRIDE;
 
 private:
     explicit Console(LocalFrame*);
 };
 
 } // namespace blink
 
 #endif // Console_h