Oilpan: make DOMWindowProperty a GC mixin.

Source/core/frame/BarProp.cpp

 /*
  * Copyright (C) 2007, 2010 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 23 matching lines @@
 #include "core/frame/LocalFrame.h"
 
 namespace blink {
 
 BarProp::BarProp(LocalFrame* frame, Type type)
     : DOMWindowProperty(frame)
     , m_type(type)
 {
 }
 
+void BarProp::trace(Visitor* visitor)
+{
+    DOMWindowProperty::trace(visitor);
+}
+
 bool BarProp::visible() const
 {
     if (!m_frame)
         return false;
     FrameHost* host = m_frame->host();
     if (!host)
         return false;
 
     switch (m_type) {
     case Locationbar:
     case Personalbar:
     case Toolbar:
         return host->chrome().toolbarsVisible();
     case Menubar:
         return host->chrome().menubarVisible();
     case Scrollbars:
         return host->chrome().scrollbarsVisible();
     case Statusbar:
         return host->chrome().statusbarVisible();
     }
 
     ASSERT_NOT_REACHED();
     return false;
 }
 
 } // namespace blink