Inherit EventTarget interface instead of duplicating its code

Source/core/page/EventSource.h

 /*
  * Copyright (C) 2009, 2012 Ericsson AB. All rights reserved.
  * Copyright (C) 2010 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.
@@ skipping 31 matching lines @@
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class Dictionary;
 class MessageEvent;
 class ResourceResponse;
 class TextResourceDecoder;
 class ThreadableLoader;
 
-class EventSource : public RefCounted<EventSource>, public ScriptWrappable, public EventTarget, private ThreadableLoaderClient, public ActiveDOMObject {
+class EventSource :  public EventTarget, public RefCounted<EventSource>, public ScriptWrappable, private ThreadableLoaderClient, public ActiveDOMObject {
     WTF_MAKE_FAST_ALLOCATED;
 public:
     static PassRefPtr<EventSource> create(ScriptExecutionContext*, const String& url, const Dictionary&, ExceptionCode&);
     virtual ~EventSource();
 
     static const unsigned long long defaultReconnectDelay;
 
     String url() const;
     bool withCredentials() const;
 
@@ skipping 59 matching lines @@
     String m_lastEventId;
     unsigned long long m_reconnectDelay;
     String m_eventStreamOrigin;
 
     EventTargetData m_eventTargetData;
 };
 
 } // namespace WebCore
 
 #endif // EventSource_h