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 10dc1bdcd89449ea8a19e4a70fda0632c6d78014..4015f906f93c4ee0894d7a7167f4d62bf1b7b7bb 100644
--- a/webrtc/media/base/videoframe.h
+++ b/webrtc/media/base/videoframe.h
@@ -51,6 +51,11 @@
   // 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.
+  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.
   virtual const VideoFrame* GetCopyWithRotationApplied() const = 0;