Inherit EventTarget interface instead of duplicating its code

Source/modules/mediastream/MediaStream.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  * Copyright (C) 2011 Ericsson AB. 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
@@ skipping 22 matching lines @@
 #include "core/platform/Timer.h"
 #include "core/platform/mediastream/MediaStreamDescriptor.h"
 #include "modules/mediastream/MediaStreamTrack.h"
 #include "wtf/RefCounted.h"
 #include "wtf/RefPtr.h"
 
 namespace WebCore {
 
 typedef int ExceptionCode;
 
-class MediaStream : public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public EventTarget, public ContextLifecycleObserver {
+class MediaStream : public EventTarget, public RefCounted<MediaStream>, public ScriptWrappable, public URLRegistrable, public MediaStreamDescriptorClient, public ContextLifecycleObserver {
 public:
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*);
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*, PassRefPtr<MediaStream>);
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*, const MediaStreamTrackVector&);
     static PassRefPtr<MediaStream> create(ScriptExecutionContext*, PassRefPtr<MediaStreamDescriptor>);
     virtual ~MediaStream();
 
     // DEPRECATED
     String label() const { return m_descriptor->id(); }
 
@@ skipping 61 matching lines @@
 
     Timer<MediaStream> m_scheduledEventTimer;
     Vector<RefPtr<Event> > m_scheduledEvents;
 };
 
 typedef Vector<RefPtr<MediaStream> > MediaStreamVector;
 
 } // namespace WebCore
 
 #endif // MediaStream_h