Delete unused cricket::VideoFrame methods MakeExclusive and CopyToFrame.

talk/app/webrtc/objc/RTCI420Frame.mm

 /*
  * libjingle
  * Copyright 2013 Google Inc.
  *
  * 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,
@@ skipping 64 matching lines @@
 }
 
 - (NSInteger)uPitch {
   return _videoFrame->GetUPitch();
 }
 
 - (NSInteger)vPitch {
   return _videoFrame->GetVPitch();
 }
 
-- (BOOL)makeExclusive {
-  return _videoFrame->MakeExclusive();
-}
-
 @end
 
 @implementation RTCI420Frame (Internal)
 
 - (instancetype)initWithVideoFrame:(cricket::VideoFrame*)videoFrame {
   if (self = [super init]) {
     // Keep a shallow copy of the video frame. The underlying frame buffer is
     // not copied.
     _videoFrame.reset(videoFrame->Copy());
   }
   return self;
 }
 
 @end