First part of work to move V8 binding integrity off of vtables.

Source/WebCore/dom/BeforeLoadEvent.h

 /*
  * Copyright (C) 2009 Apple 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 46 matching lines @@
         return adoptRef(new BeforeLoadEvent(type, initializer));
     }
 
     const String& url() const { return m_url; }
 
     virtual const AtomicString& interfaceName() const { return eventNames().interfaceForBeforeLoadEvent; }
 
 private:
     BeforeLoadEvent()
     {
+        ScriptWrappable::init(this);
     }
 
     explicit BeforeLoadEvent(const String& url)
         : Event(eventNames().beforeloadEvent, false, true)
         , m_url(url)
     {
+        ScriptWrappable::init(this);
     }
 
     BeforeLoadEvent(const AtomicString& type, const BeforeLoadEventInit& initializer)
         : Event(type, initializer)
         , m_url(initializer.url)
     {
+        ScriptWrappable::init(this);
     }
 
     String m_url;
 };
 
 } // namespace WebCore
 
 #endif // BeforeLoadEvent_h