Revert of Delete method cricket::VideoFrame::Copy.

webrtc/media/engine/webrtcvideoframe.h

 /*
  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 75 matching lines @@
   const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& video_frame_buffer()
       const override;
 
   uint32_t transport_frame_id() const override;
 
   int64_t timestamp_us() const override;
   void set_timestamp_us(int64_t time_us) override;
 
   webrtc::VideoRotation rotation() const override;
 
+  VideoFrame* Copy() const override;
+
   size_t ConvertToRgbBuffer(uint32_t to_fourcc,
                             uint8_t* buffer,
                             size_t size,
                             int stride_rgb) const override;
 
   const VideoFrame* GetCopyWithRotationApplied() const override;
 
  protected:
   // Creates a frame from a raw sample with FourCC |format| and size |w| x |h|.
   // |h| can be negative indicating a vertically flipped image.
@@ skipping 22 matching lines @@
   webrtc::VideoRotation rotation_;
 
   // This is mutable as the calculation is expensive but once calculated, it
   // remains const.
   mutable std::unique_ptr<VideoFrame> rotated_frame_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_ENGINE_WEBRTCVIDEOFRAME_H_