Update VideoFrameBuffer-related methods to not use references to scoped_refptr.

webrtc/video_frame.h

 /*
  *  Copyright (c) 2014 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 102 matching lines @@
   // only if the object was default-constructed.
   // TODO(nisse): Deprecated. Should be deleted in the cricket::VideoFrame and
   // webrtc::VideoFrame merge. The intention is that video_frame_buffer() never
   // should return nullptr. To handle potentially uninitialized or non-existent
   // frames, consider using rtc::Optional. Otherwise, IsZeroSize() can be
   // replaced by video_frame_buffer() == nullptr.
   bool IsZeroSize() const;
 
   // Return the underlying buffer. Never nullptr for a properly
   // initialized VideoFrame.
-  // Creating a new reference breaks the HasOneRef and IsMutable
-  // logic. So return a const ref to our reference.
-  const rtc::scoped_refptr<webrtc::VideoFrameBuffer>& video_frame_buffer()
-      const;
+  rtc::scoped_refptr<webrtc::VideoFrameBuffer> video_frame_buffer() const;
 
   // Return true if the frame is stored in a texture.
   bool is_texture() const {
     return video_frame_buffer() &&
            video_frame_buffer()->native_handle() != nullptr;
   }
 
  private:
   // An opaque reference counted handle that stores the pixel data.
   rtc::scoped_refptr<webrtc::VideoFrameBuffer> video_frame_buffer_;
@@ skipping 46 matching lines @@
   int qp_ = -1;  // Quantizer value.
 
   // When an application indicates non-zero values here, it is taken as an
   // indication that all future frames will be constrained with those limits
   // until the application indicates a change again.
   PlayoutDelay playout_delay_ = {-1, -1};
 };
 
 }  // namespace webrtc
 #endif  // WEBRTC_VIDEO_FRAME_H_