Oilpan: make DOMWindowProperty a GC mixin.

Source/core/frame/Console.cpp

 /*
  * 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 37 matching lines @@
 
 Console::Console(LocalFrame* frame)
     : DOMWindowProperty(frame)
 {
 }
 
 Console::~Console()
 {
 }
 
+void Console::trace(Visitor* visitor)
+{
+    ConsoleBase::trace(visitor);
+    DOMWindowProperty::trace(visitor);
+}
+
 ExecutionContext* Console::context()
 {
     if (!m_frame)
         return 0;
     return m_frame->document();
 }
 
 void Console::reportMessageToConsole(PassRefPtrWillBeRawPtr<ConsoleMessage> consoleMessage)
 {
     if (!m_frame)
         return;
 
     m_frame->console().addMessage(consoleMessage);
 }
 
 PassRefPtrWillBeRawPtr<MemoryInfo> Console::memory() const
 {
     // FIXME: Because we create a new object here each time,
     // console.memory !== console.memory, which seems wrong.
     return MemoryInfo::create();
 }
 
 } // namespace blink