Remove leak of objects between isolated worlds on custom events.

Source/core/dom/PopStateEvent.cpp

 /*
  * Copyright (C) 2009 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 29 matching lines @@
 PopStateEvent::PopStateEvent()
     : Event(eventNames().popstateEvent, false, true)
     , m_serializedState(0)
     , m_history(0)
 {
     ScriptWrappable::init(this);
 }
 
 PopStateEvent::PopStateEvent(const AtomicString& type, const PopStateEventInit& initializer)
     : Event(type, initializer)
-    , m_state(initializer.state)
     , m_serializedState(0)
     , m_history(0)
 {
     ScriptWrappable::init(this);
 }
 
 PopStateEvent::PopStateEvent(PassRefPtr<SerializedScriptValue> serializedState, PassRefPtr<History> history)
     : Event(eventNames().popstateEvent, false, true)
     , m_serializedState(serializedState)
     , m_history(history)
@@ skipping 19 matching lines @@
 {
     return adoptRef(new PopStateEvent(type, initializer));
 }
 
 const AtomicString& PopStateEvent::interfaceName() const
 {
     return eventNames().interfaceForPopStateEvent;
 }
 
 } // namespace WebCore