Prevent 'removetrack' events from firing when all inband text tracks are removed.

Source/core/html/track/InbandTextTrack.h

 /*
  * 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:
  * 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 29 matching lines @@
 class Document;
 class MediaPlayer;
 class TextTrackCue;
 
 class InbandTextTrack FINAL : public TextTrack, public blink::WebInbandTextTrackClient {
 public:
     static PassRefPtr<InbandTextTrack> create(Document&, TextTrackClient*, blink::WebInbandTextTrack*);
     virtual ~InbandTextTrack();
 
     size_t inbandTrackIndex();
-    void trackRemoved();
+    virtual void setTrackList(TextTrackList*) OVERRIDE FINAL;
 
 private:
     InbandTextTrack(Document&, TextTrackClient*, blink::WebInbandTextTrack*);
 
     virtual void addWebVTTCue(double, double, const blink::WebString&, const blink::WebString&, const blink::WebString&) OVERRIDE;
 
     blink::WebInbandTextTrack* m_webTrack;
 };
 
 } // namespace WebCore
 
 #endif