Lazily generate HistoryItem's serialized form state

Source/core/loader/FrameLoader.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * 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:
  *
@@ skipping 168 matching lines @@
 
     bool shouldClose();
 
     void started();
 
     bool allowPlugins(ReasonForCallingAllowPlugins);
 
     void updateForSameDocumentNavigation(const KURL&, SameDocumentNavigationSource, PassRefPtr<SerializedScriptValue>, UpdateBackForwardListPolicy);
 
     HistoryItem* currentItem() const { return m_currentItem.get(); }
-    void markDocumentStateDirty();
-    void saveDocumentState();
     void saveScrollState();
     void clearScrollPositionAndViewState();
 
     void restoreScrollPositionAndViewState();
 
 private:
     bool allChildrenAreComplete() const; // immediate children, not all descendants
 
     void completed();
 
@@ skipping 81 matching lines @@
 
     bool m_didAccessInitialDocument;
     Timer<FrameLoader> m_didAccessInitialDocumentTimer;
 
     SandboxFlags m_forcedSandboxFlags;
 };
 
 } // namespace WebCore
 
 #endif // FrameLoader_h