Remove TextTrackCue::isVTTCue

Source/core/html/track/vtt/VTTCue.h

 /*
  * Copyright (c) 2013, Opera Software ASA. 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 52 matching lines @@
 
 class VTTCue FINAL : public TextTrackCue, public ScriptWrappable {
 public:
     static PassRefPtr<VTTCue> create(Document& document, double startTime, double endTime, const String& text)
     {
         return adoptRef(new VTTCue(document, startTime, endTime, text));
     }
 
     virtual ~VTTCue();
 
-    virtual bool isVTTCue() const OVERRIDE { return true; }
-
     const String& vertical() const;
     void setVertical(const String&, ExceptionState&);
 
     bool snapToLines() const { return m_snapToLines; }
     void setSnapToLines(bool);
 
     int line() const { return m_linePosition; }
     void setLine(int, ExceptionState&);
 
     int position() const { return m_textPosition; }
@@ skipping 111 matching lines @@
 
 inline VTTCue* toVTTCue(TextTrackCue* cue)
 {
     // VTTCue is currently the only TextTrackCue subclass.
     return static_cast<VTTCue*>(cue);
 }
 
 } // namespace WebCore
 
 #endif