Inherit EventTarget interface instead of duplicating its code

Source/modules/mediastream/MediaStreamTrack.h

Index: Source/modules/mediastream/MediaStreamTrack.h
diff --git a/Source/modules/mediastream/MediaStreamTrack.h b/Source/modules/mediastream/MediaStreamTrack.h
index 33b44173994517d295ea540f5fd4634619dcedc4..129b18835f73da538e225220793114b68c3501cd 100644
--- a/Source/modules/mediastream/MediaStreamTrack.h
+++ b/Source/modules/mediastream/MediaStreamTrack.h
@@ -43,7 +43,7 @@ namespace WebCore {
 class MediaStreamComponent;
 class MediaStreamTrackSourcesCallback;
 
-class MediaStreamTrack : public RefCounted<MediaStreamTrack>, public ScriptWrappable, public ActiveDOMObject, public EventTarget, public MediaStreamSource::Observer {
+class MediaStreamTrack : public EventTarget, public RefCounted<MediaStreamTrack>, public ScriptWrappable, public ActiveDOMObject, public MediaStreamSource::Observer {
 public:
     static PassRefPtr<MediaStreamTrack> create(ScriptExecutionContext*, MediaStreamComponent*);
     virtual ~MediaStreamTrack();