Don't fire popstate event on initial document load

Source/core/frame/DOMWindow.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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 432 matching lines @@
 void DOMWindow::dispatchWindowLoadEvent()
 {
     ASSERT(!NoEventDispatchAssertion::isEventDispatchForbidden());
     dispatchLoadEvent();
 }
 
 void DOMWindow::documentWasClosed()
 {
     dispatchWindowLoadEvent();
     enqueuePageshowEvent(PageshowEventNotPersisted);
-    enqueuePopstateEvent(m_pendingStateObject ? m_pendingStateObject.release() : SerializedScriptValue::nullValue());
+    if (m_pendingStateObject)
+        enqueuePopstateEvent(m_pendingStateObject.release());
 }
 
 void DOMWindow::enqueuePageshowEvent(PageshowEventPersistence persisted)
 {
     // FIXME: https://bugs.webkit.org/show_bug.cgi?id=36334 Pageshow event needs to fire asynchronously.
     dispatchEvent(PageTransitionEvent::create(EventTypeNames::pageshow, persisted), m_document.get());
 }
 
 void DOMWindow::enqueueHashchangeEvent(const String& oldURL, const String& newURL)
 {
@@ skipping 1401 matching lines @@
     return static_cast<DOMWindowLifecycleNotifier&>(LifecycleContext<DOMWindow>::lifecycleNotifier());
 }
 
 PassOwnPtr<LifecycleNotifier<DOMWindow> > DOMWindow::createLifecycleNotifier()
 {
     return DOMWindowLifecycleNotifier::create(this);
 }
 
 
 } // namespace WebCore