Oilpan: make DOMWindowProperty a GC mixin.

Source/modules/indexeddb/DOMWindowIndexedDatabase.cpp

 /*
  * 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 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 21 matching lines @@
 #include "modules/indexeddb/IDBFactory.h"
 
 namespace blink {
 
 DOMWindowIndexedDatabase::DOMWindowIndexedDatabase(LocalDOMWindow& window)
     : DOMWindowProperty(window.frame())
     , m_window(window)
 {
 }
 
-DOMWindowIndexedDatabase::~DOMWindowIndexedDatabase()
-{
-}
+DEFINE_EMPTY_DESTRUCTOR_WILL_BE_REMOVED(DOMWindowIndexedDatabase);
 
 void DOMWindowIndexedDatabase::trace(Visitor* visitor)
 {
     visitor->trace(m_idbFactory);
     WillBeHeapSupplement<LocalDOMWindow>::trace(visitor);
+    DOMWindowProperty::trace(visitor);
 }
 
 const char* DOMWindowIndexedDatabase::supplementName()
 {
     return "DOMWindowIndexedDatabase";
 }
 
 DOMWindowIndexedDatabase& DOMWindowIndexedDatabase::from(LocalDOMWindow& window)
 {
     DOMWindowIndexedDatabase* supplement = static_cast<DOMWindowIndexedDatabase*>(WillBeHeapSupplement<LocalDOMWindow>::from(window, supplementName()));
@@ skipping 33 matching lines @@
 
     if (!m_window.isCurrentlyDisplayedInFrame())
         return 0;
 
     if (!m_idbFactory)
         m_idbFactory = IDBFactory::create(IndexedDBClient::create());
     return m_idbFactory.get();
 }
 
 } // namespace blink