Lazily generate HistoryItem's serialized form state

Source/core/loader/HistoryItem.h

 /*
  * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Research In Motion Limited. 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
@@ skipping 18 matching lines @@
 
 #include "bindings/v8/SerializedScriptValue.h"
 #include "platform/geometry/IntPoint.h"
 #include "platform/weborigin/Referrer.h"
 #include "wtf/RefCounted.h"
 #include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
 class Document;
+class DocumentState;
 class FormData;
 class HistoryItem;
 class Image;
 class KURL;
 class ResourceRequest;
 
 typedef Vector<RefPtr<HistoryItem> > HistoryItemVector;
 
 class HistoryItem : public RefCounted<HistoryItem> {
 public:
@@ skipping 13 matching lines @@
     FormData* formData();
     const AtomicString& formContentType() const;
 
     const IntPoint& scrollPoint() const;
     void setScrollPoint(const IntPoint&);
     void clearScrollPoint();
 
     float pageScaleFactor() const;
     void setPageScaleFactor(float);
 
-    const Vector<String>& documentState() const;
+    Vector<String> getReferencedFilePaths();
+    const Vector<String>& documentState();
     void setDocumentState(const Vector<String>&);
+    void setDocumentState(DocumentState*);
     void clearDocumentState();
 
     void setURL(const KURL&);
     void setURLString(const String&);
     void setReferrer(const Referrer&);
     void setTarget(const String&);
 
     void setStateObject(PassRefPtr<SerializedScriptValue>);
     SerializedScriptValue* stateObject() const { return m_stateObject.get(); }
 
@@ skipping 18 matching lines @@
 
 private:
     HistoryItem();
 
     String m_urlString;
     Referrer m_referrer;
     String m_target;
 
     IntPoint m_scrollPoint;
     float m_pageScaleFactor;
-    Vector<String> m_documentState;
+    Vector<String> m_documentStateVector;
+    RefPtr<DocumentState> m_documentState;
 
     HistoryItemVector m_children;
 
     // If two HistoryItems have the same item sequence number, then they are
     // clones of one another. Traversing history from one such HistoryItem to
     // another is a no-op. HistoryItem clones are created for parent and
     // sibling frames when only a subframe navigates.
     int64_t m_itemSequenceNumber;
 
     // If two HistoryItems have the same document sequence number, then they
     // refer to the same instance of a document. Traversing history from one
     // such HistoryItem to another preserves the document.
     int64_t m_documentSequenceNumber;
 
     // Support for HTML5 History
     RefPtr<SerializedScriptValue> m_stateObject;
 
     // info used to repost form data
     RefPtr<FormData> m_formData;
     AtomicString m_formContentType;
 
 }; // class HistoryItem
 
 } // namespace WebCore
 
 #endif // HISTORYITEM_H