Remove Apple's unused implementation of private browsing from WebCore

Source/WebCore/platform/graphics/MediaPlayerPrivate.h

 /*
  * Copyright (C) 2009, 2010, 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 136 matching lines @@
 
     virtual unsigned decodedFrameCount() const { return 0; }
     virtual unsigned droppedFrameCount() const { return 0; }
     virtual unsigned audioDecodedByteCount() const { return 0; }
     virtual unsigned videoDecodedByteCount() const { return 0; }
 
     void getSitesInMediaCache(Vector<String>&) { }
     void clearMediaCache() { }
     void clearMediaCacheForSite(const String&) { }
 
-    virtual void setPrivateBrowsingMode(bool) { }
-
     virtual String engineDescription() const { return emptyString(); }
 
 #if ENABLE(WEB_AUDIO)
     virtual AudioSourceProvider* audioSourceProvider() { return 0; }
 #endif
 
 #if ENABLE(ENCRYPTED_MEDIA)
     virtual MediaPlayer::MediaKeyException addKey(const String&, const unsigned char*, unsigned, const unsigned char*, unsigned, const String&) { return MediaPlayer::KeySystemNotSupported; }
     virtual MediaPlayer::MediaKeyException generateKeyRequest(const String&, const unsigned char*, unsigned) { return MediaPlayer::KeySystemNotSupported; }
     virtual MediaPlayer::MediaKeyException cancelKeyRequest(const String&, const String&) { return MediaPlayer::KeySystemNotSupported; }
@@ skipping 11 matching lines @@
 
 #if USE(GSTREAMER)
     virtual void simulateAudioInterruption() { }
 #endif
 };
 
 }
 
 #endif
 #endif