Oilpan: make DOMWindowProperty a GC mixin.

Source/modules/quota/DOMWindowQuota.cpp

 /*
  * Copyright (C) 2012 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 25 matching lines @@
 #include "modules/quota/DeprecatedStorageInfo.h"
 #include "wtf/PassRefPtr.h"
 
 namespace blink {
 
 DOMWindowQuota::DOMWindowQuota(LocalDOMWindow& window)
     : DOMWindowProperty(window.frame())
 {
 }
 
-DOMWindowQuota::~DOMWindowQuota()
-{
-}
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(DOMWindowQuota);
 
 const char* DOMWindowQuota::supplementName()
 {
     return "DOMWindowQuota";
 }
 
 // static
 DOMWindowQuota& DOMWindowQuota::from(LocalDOMWindow& window)
 {
     DOMWindowQuota* supplement = static_cast<DOMWindowQuota*>(WillBeHeapSupplement<LocalDOMWindow>::from(window, supplementName()));
@@ skipping 14 matching lines @@
 {
     if (!m_storageInfo && frame())
         m_storageInfo = DeprecatedStorageInfo::create();
     return m_storageInfo.get();
 }
 
 void DOMWindowQuota::trace(Visitor* visitor)
 {
     visitor->trace(m_storageInfo);
     WillBeHeapSupplement<LocalDOMWindow>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
 }
 
 } // namespace blink