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

webrtc/media/base/videoframe.h

Index: webrtc/media/base/videoframe.h
diff --git a/webrtc/media/base/videoframe.h b/webrtc/media/base/videoframe.h
index 3dcbb4efa5150341ac5106b92e18d3709bcde3f6..a1393499f9e72742ba5792e790c09cf5fe52baf5 100644
--- a/webrtc/media/base/videoframe.h
+++ b/webrtc/media/base/videoframe.h
@@ -58,6 +58,16 @@
   // Indicates the rotation angle in degrees.
   virtual webrtc::VideoRotation rotation() const = 0;
 
+  // Make a shallow copy of the frame. The frame buffer itself is not copied.
+  // Both the current and new VideoFrame will share a single reference-counted
+  // frame buffer.
+
+  // TODO(nisse): Deprecated, to be deleted in the cricket::VideoFrame and
+  // webrtc::VideoFrame merge. To make a copy, use the cricket::WebRtcVideoFrame
+  // constructor passing video_frame_buffer(), rotation() and timestamp_us() as
+  // arguments.
+  virtual VideoFrame *Copy() const = 0;
+
   // Return a copy of frame which has its pending rotation applied. The
   // ownership of the returned frame is held by this frame.