Inherit EventTarget interface instead of duplicating its code

Source/core/html/track/TextTrackCue.h

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) 2012, 2013 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 50 matching lines @@
 protected:
     TextTrackCueBox(Document*, TextTrackCue*);
 
     virtual RenderObject* createRenderer(RenderStyle*) OVERRIDE;
 
     TextTrackCue* m_cue;
 };
 
 // ----------------------------
 
-class TextTrackCue : public RefCounted<TextTrackCue>, public ScriptWrappable, public EventTarget {
+class TextTrackCue :  public EventTarget, public RefCounted<TextTrackCue>, public ScriptWrappable {
 public:
     static PassRefPtr<TextTrackCue> create(ScriptExecutionContext* context, double start, double end, const String& content)
     {
         return adoptRef(new TextTrackCue(context, start, end, content));
     }
 
     static const AtomicString& cueShadowPseudoId()
     {
         DEFINE_STATIC_LOCAL(const AtomicString, cue, ("cue", AtomicString::ConstructFromLiteral));
         return cue;
@@ skipping 190 matching lines @@
 
     std::pair<float, float> m_displayPosition;
 #if ENABLE(WEBVTT_REGIONS)
     String m_regionId;
 #endif
 };
 
 } // namespace WebCore
 
 #endif