Update HTTPHeaderMap wrappers to use AtomicString type for header values

Source/platform/network/WebSocketHandshakeResponse.cpp

 /*
  * Copyright (C) 2010 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 52 matching lines @@
 void WebSocketHandshakeResponse::setStatusText(const String& statusText)
 {
     m_statusText = statusText;
 }
 
 const HTTPHeaderMap& WebSocketHandshakeResponse::headerFields() const
 {
     return m_headerFields;
 }
 
-void WebSocketHandshakeResponse::addHeaderField(const AtomicString& name, const String& value)
+void WebSocketHandshakeResponse::addHeaderField(const AtomicString& name, const AtomicString& value)
 {
     m_headerFields.add(name, value);
 }
 
 void WebSocketHandshakeResponse::clearHeaderFields()
 {
     m_headerFields.clear();
 }
 
 } // namespace WebCore