Remove the logic for de-duplicating in-band text track cues

Source/core/html/track/TextTrack.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  * Copyright (C) 2011, 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
@@ skipping 81 matching lines @@
     void setReadinessState(ReadinessState state) { m_readinessState = state; }
 
     TextTrackCueList* cues();
     TextTrackCueList* activeCues() const;
 
     void clearClient() { m_client = 0; }
     TextTrackClient* client() { return m_client; }
 
     void addCue(PassRefPtr<TextTrackCue>);
     void removeCue(TextTrackCue*, ExceptionState&);
-    bool hasCue(TextTrackCue*);
 
     VTTRegionList* regions();
     void addRegion(PassRefPtr<VTTRegion>);
     void removeRegion(VTTRegion*, ExceptionState&);
 
     void cueWillChange(TextTrackCue*);
     void cueDidChange(TextTrackCue*);
 
     DEFINE_ATTRIBUTE_EVENT_LISTENER(cuechange);
 
@@ skipping 43 matching lines @@
     TextTrackType m_trackType;
     ReadinessState m_readinessState;
     int m_trackIndex;
     int m_renderedTrackIndex;
     bool m_hasBeenConfigured;
 };
 
 } // namespace WebCore
 
 #endif