Remove TextTrackClient interface to simplify TextTrack code.

Source/core/html/track/TextTrackList.h

 /*
  * Copyright (C) 2011, 2012 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.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 50 matching lines @@
     void remove(TextTrack*);
 
     // EventTarget
     virtual const AtomicString& interfaceName() const OVERRIDE;
     virtual ExecutionContext* executionContext() const OVERRIDE;
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(addtrack);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(change);
     DEFINE_ATTRIBUTE_EVENT_LISTENER(removetrack);
 
-    void clearOwnerAndClients();
+    void clearOwner();
     HTMLMediaElement* owner() const;
 
     void scheduleChangeEvent();
     void removeAllInbandTracks();
 
 private:
     explicit TextTrackList(HTMLMediaElement*);
 
     void scheduleTrackEvent(const AtomicString& eventName, PassRefPtr<TextTrack>);
 
     void scheduleAddTrackEvent(PassRefPtr<TextTrack>);
     void scheduleRemoveTrackEvent(PassRefPtr<TextTrack>);
 
     void invalidateTrackIndexesAfterTrack(TextTrack*);
 
     HTMLMediaElement* m_owner;
 
     OwnPtr<GenericEventQueue> m_asyncEventQueue;
 
     Vector<RefPtr<TextTrack> > m_addTrackTracks;
     Vector<RefPtr<TextTrack> > m_elementTracks;
     Vector<RefPtr<TextTrack> > m_inbandTracks;
 };
 
 } // namespace WebCore
 
 #endif