Avoid race in VideoReceiveStream shutdown

webrtc/video/video_receive_stream.cc

Index: webrtc/video/video_receive_stream.cc
diff --git a/webrtc/video/video_receive_stream.cc b/webrtc/video/video_receive_stream.cc
index ad9beb35e75384801cf03d264f935a7137a9b383..2ddec191807257d2d98dc48e2fa34aa240273403 100644
--- a/webrtc/video/video_receive_stream.cc
+++ b/webrtc/video/video_receive_stream.cc
@@ -267,7 +267,7 @@ void VideoReceiveStream::Start() {
 
 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();