Avoid race in VideoReceiveStream shutdown

webrtc/video/video_receive_stream.cc

 /*
  *  Copyright (c) 2013 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 249 matching lines @@
   // Register the channel to receive stats updates.
   call_stats_->RegisterStatsObserver(video_stream_decoder_.get());
   // Start the decode thread
   decode_thread_.Start();
   decode_thread_.SetPriority(rtc::kHighestPriority);
   rtp_stream_receiver_.StartReceive();
 }
 
 void VideoReceiveStream::Stop() {
   rtp_stream_receiver_.StopReceive();
-  video_receiver_.TriggerDecoderShutdown();
+  video_receiver_.TriggerDecoderShutdown();  // Releases waiting decoder thread.

[pbos-webrtc, 2016/07/13 16:43:05]

Put something to the effect of this making decode_thread_ stop directly (instead
of waiting for a timeout), and that it should be called before joining the
thread.

[sprang_webrtc, 2016/07/13 16:51:32]

Done.

   decode_thread_.Stop();
   call_stats_->DeregisterStatsObserver(video_stream_decoder_.get());
   video_stream_decoder_.reset();
   incoming_video_stream_.reset();
   transport_adapter_.Disable();
 }
 
 void VideoReceiveStream::SetSyncChannel(VoiceEngine* voice_engine,
                                         int audio_channel_id) {
   if (voice_engine && audio_channel_id != -1) {
@@ skipping 78 matching lines @@
     const std::vector<uint16_t>& sequence_numbers) {
   rtp_stream_receiver_.RequestPacketRetransmit(sequence_numbers);
 }
 
 void VideoReceiveStream::RequestKeyFrame() {
   rtp_stream_receiver_.RequestKeyFrame();
 }
 
 }  // namespace internal
 }  // namespace webrtc