Update HTTPHeaderMap wrappers to use AtomicString type for header values

Source/core/history/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 41 matching lines @@
     PassRefPtr<HistoryItem> copy() const;
 
     // Resets the HistoryItem to its initial state, as returned by create().
     void reset();
 
     const String& originalURLString() const;
     const String& urlString() const;
     KURL url() const;
     KURL originalURL() const;
 
-    const String& referrer() const;
+    const AtomicString& referrer() const;
     const String& target() const;
 
     FormData* formData();
-    String formContentType() const;
+    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;
     void setDocumentState(const Vector<String>&);
     void clearDocumentState();
 
     void setURL(const KURL&);
     void setURLString(const String&);
     void setOriginalURLString(const String&);
-    void setReferrer(const String&);
+    void setReferrer(const AtomicString&);
     void setTarget(const String&);
 
     void setStateObject(PassRefPtr<SerializedScriptValue> object);
     SerializedScriptValue* stateObject() const { return m_stateObject.get(); }
 
     void setItemSequenceNumber(long long number) { m_itemSequenceNumber = number; }
     long long itemSequenceNumber() const { return m_itemSequenceNumber; }
 
     void setDocumentSequenceNumber(long long number) { m_documentSequenceNumber = number; }
     long long documentSequenceNumber() const { return m_documentSequenceNumber; }
 
     void setTargetFrameID(int64_t id) { m_targetFrameID = id; }
     int64_t targetFrameID() const { return m_targetFrameID; }
 
     void setFormInfoFromRequest(const ResourceRequest&);
     void setFormData(PassRefPtr<FormData>);
-    void setFormContentType(const String&);
+    void setFormContentType(const AtomicString&);
 
     void addChildItem(PassRefPtr<HistoryItem>);
     const HistoryItemVector& children() const;
     void clearChildren();
 
     bool isCurrentDocument(Document*) const;
 
 private:
     HistoryItem();
     explicit HistoryItem(const HistoryItem&);
 
     String m_urlString;
     String m_originalURLString;
-    String m_referrer;
+    AtomicString m_referrer;
     String m_target;
 
     IntPoint m_scrollPoint;
     float m_pageScaleFactor;
     Vector<String> 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;
 
     int64_t m_targetFrameID;
 
     // Support for HTML5 History
     RefPtr<SerializedScriptValue> m_stateObject;
 
     // info used to repost form data
     RefPtr<FormData> m_formData;
-    String m_formContentType;
+    AtomicString m_formContentType;
 
 }; //class HistoryItem
 
 } //namespace WebCore
 
 #endif // HISTORYITEM_H