Add support for BeforeUnloadEvent

Source/core/dom/BeforeUnloadEvent.h

 /*
  * Copyright (C) 2001 Peter Kelly (pmk@post.com)
  * Copyright (C) 2001 Tobias Anton (anton@stud.fbi.fh-darmstadt.de)
  * Copyright (C) 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006 Apple Computer, Inc.
+ * Copyright (C) 2013 Samsung Electronics.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  *
  */
 
 #ifndef BeforeUnloadEvent_h
 #define BeforeUnloadEvent_h
 
 #include "core/dom/Event.h"
+#include "core/dom/EventNames.h"
 
 namespace WebCore {
 
     class BeforeUnloadEvent : public Event {
     public:
         virtual ~BeforeUnloadEvent();
 
         static PassRefPtr<BeforeUnloadEvent> create()
         {
             return adoptRef(new BeforeUnloadEvent);
         }
 
-        virtual bool storesResultAsString() const;
-        virtual void storeResult(const String&);
+        void setReturnValue(const String&);

[arv (Not doing code reviews), 2013/08/23 13:56:49]

Now that this is no longer virtual you might as well move the single line
implementation here.

[do-not-use, 2013/08/23 14:27:54]

Done.

+        String returnValue() const { return m_returnValue; }
 
-        String result() const { return m_result; }
+        virtual const AtomicString& interfaceName() const OVERRIDE { return eventNames().interfaceForBeforeUnloadEvent; }
 
     private:
         BeforeUnloadEvent();
 
-        String m_result;
+        String m_returnValue;
     };
 
 } // namespace WebCore
 
 #endif // BeforeUnloadEvent_h