Remove MediaControls::textTracksChanged

Source/core/html/shadow/MediaControls.h

 /*
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Google 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
@@ skipping 40 matching lines @@
 
     void beginScrubbing();
     void endScrubbing();
 
     void updateCurrentTimeDisplay();
 
     void updateVolume();
 
     void changedClosedCaptionsVisibility();
     void refreshClosedCaptionsButtonVisibility();
-    void textTracksChanged();
 
     void enteredFullscreen();
     void exitedFullscreen();
 
     void startedCasting();
     void stoppedCasting();
     void refreshCastButtonVisibility();
     void showOverlayCastButton();
 
     void updateTextTrackDisplay();
@@ skipping 67 matching lines @@
     bool m_isMouseOverControls : 1;
     bool m_isPausedForScrubbing : 1;
     bool m_wasLastEventTouch : 1;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(MediaControls, isMediaControls());
 
 }
 
 #endif