Remove WebInbandTextTrack::isDefault()

Source/platform/graphics/media/InbandTextTrackPrivate.h

 /*
  * Copyright (C) 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 38 matching lines @@
 
     enum Mode { Disabled, Hidden, Showing };
     virtual void setMode(Mode mode) { m_mode = mode; };
     virtual InbandTextTrackPrivate::Mode mode() const { return m_mode; }
 
     enum Kind { Subtitles, Captions, Descriptions, Chapters, Metadata, None };
     virtual Kind kind() const { return Subtitles; }
 
     virtual AtomicString label() const { return emptyAtom; }
     virtual AtomicString language() const { return emptyAtom; }
-    virtual bool isDefault() const { return false; }
 
     virtual int textTrackIndex() const { return 0; }
 
 protected:
     InbandTextTrackPrivate()
         : m_client(0)
         , m_mode(Disabled)
     {
     }
 
 private:
     InbandTextTrackPrivateClient* m_client;
     Mode m_mode;
 };
 
 } // namespace WebCore
 
 #endif