Inherit EventTarget interface instead of duplicating its code

Source/modules/mediasource/SourceBufferList.h

 /*
  * Copyright (C) 2013 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 23 matching lines @@
 #include "bindings/v8/ScriptWrappable.h"
 #include "core/dom/EventTarget.h"
 #include "wtf/RefCounted.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class SourceBuffer;
 class GenericEventQueue;
 
-class SourceBufferList : public RefCounted<SourceBufferList>, public ScriptWrappable, public EventTarget {
+class SourceBufferList : public EventTarget, public RefCounted<SourceBufferList>, public ScriptWrappable {
 public:
     static PassRefPtr<SourceBufferList> create(ScriptExecutionContext* context, GenericEventQueue* asyncEventQueue)
     {
         return adoptRef(new SourceBufferList(context, asyncEventQueue));
     }
     virtual ~SourceBufferList();
 
     unsigned long length() const { return m_list.size(); }
     SourceBuffer* item(unsigned long index) const { return (index < m_list.size()) ? m_list[index].get() : 0; }
 
@@ skipping 24 matching lines @@
     EventTargetData m_eventTargetData;
     ScriptExecutionContext* m_scriptExecutionContext;
     GenericEventQueue* m_asyncEventQueue;
 
     Vector<RefPtr<SourceBuffer> > m_list;
 };
 
 } // namespace WebCore
 
 #endif