Add support for BeforeUnloadEvent

Source/core/dom/BeforeUnloadEvent.cpp

-/**
+/*
  * 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, 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.
  */
 
 #include "config.h"
 #include "core/dom/BeforeUnloadEvent.h"
 
 #include "core/dom/EventNames.h"
 
 namespace WebCore {
 
 BeforeUnloadEvent::BeforeUnloadEvent()
     : Event(eventNames().beforeunloadEvent, false, true)
 {
+    ScriptWrappable::init(this);
 }
 
 BeforeUnloadEvent::~BeforeUnloadEvent()
 {
 }
 
-bool BeforeUnloadEvent::storesResultAsString() const
+bool BeforeUnloadEvent::isBeforeUnloadEvent() const
 {
     return true;
 }
 
-void BeforeUnloadEvent::storeResult(const String& s)
-{
-    m_result = s;
-}
-
 } // namespace WebCore