Make WebRtcVideoChannel2::WebRtcVideoSendStream implement rtc::VideoRendererInterface.

talk/app/webrtc/rtpsender.cc

 /*
  * libjingle
  * Copyright 2015 Google Inc.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  *  1. Redistributions of source code must retain the above copyright notice,
  *     this list of conditions and the following disclaimer.
  *  2. Redistributions in binary form must reproduce the above copyright notice,
@@ skipping 250 matching lines @@
     LOG(LS_ERROR) << "SetTrack can't be called on a stopped RtpSender.";
     return false;
   }
   if (track && track->kind() != MediaStreamTrackInterface::kVideoKind) {
     LOG(LS_ERROR) << "SetTrack called on video RtpSender with " << track->kind()
                   << " track.";
     return false;
   }
   VideoTrackInterface* video_track = static_cast<VideoTrackInterface*>(track);
 
+  // TODO(nisse): To make code a little simpler, ensure that
+  // GetSink(0) returns NULL, and that AddSink and RemoveSink with
+  // NULL is safe.
+  rtc::VideoSinkInterface<cricket::VideoFrame>* sink =
+      provider_->GetSink(ssrc_);
+
   // Detach from old track.
   if (track_) {
     track_->UnregisterObserver(this);
+    if (sink)
+      track_->RemoveSink(sink);
   }
 
   // Attach to new track.
   bool prev_can_send_track = can_send_track();
   track_ = video_track;
   if (track_) {
     cached_track_enabled_ = track_->enabled();
     track_->RegisterObserver(this);
+    if (sink)
+      video_track->AddSink(sink);
   }
 
   // Update video provider.
   if (can_send_track()) {
     VideoSourceInterface* source = track_->GetSource();
     // TODO(deadbeef): If SetTrack is called with a disabled track, and the
     // previous track was enabled, this could cause a frame from the new track
     // to slip out. Really, what we need is for SetCaptureDevice and
     // SetVideoSend
     // to be combined into one atomic operation, all the way down to
@@ skipping 26 matching lines @@
   }
 }
 
 void VideoRtpSender::Stop() {
   // TODO(deadbeef): Need to do more here to fully stop sending packets.
   if (stopped_) {
     return;
   }
   if (track_) {
     track_->UnregisterObserver(this);
+
+    rtc::VideoSinkInterface<cricket::VideoFrame>* sink =
+        provider_->GetSink(ssrc_);
+    if (sink)
+      track_->RemoveSink(sink);
+    else
+      LOG(LS_ERROR)
+          << "VideoRtpSender::Stop called with a NULL sink. Too late???";

[perkj_webrtc, 2016/01/26 15:40:56]

Is there ever a case when this is fine? If not- I think we should remove the if
(sink) to catch the error.

[nisse-webrtc, 2016/01/28 08:24:53]

I think track_->RemoveSink(nullptr) will succeed and do nothing (and I think
that makes some sense). So to catch the error, I think we have to check for it
here. Possibly using RTC_CHECK?

   }
   if (can_send_track()) {
     provider_->SetCaptureDevice(ssrc_, nullptr);
     provider_->SetVideoSend(ssrc_, false, nullptr);
   }
   stopped_ = true;
 }
 
 void VideoRtpSender::SetVideoSend() {
   RTC_DCHECK(!stopped_ && can_send_track());
   const cricket::VideoOptions* options = nullptr;
   VideoSourceInterface* source = track_->GetSource();
   if (track_->enabled() && source) {
     options = source->options();
   }
   provider_->SetVideoSend(ssrc_, track_->enabled(), options);
 }
 
 }  // namespace webrtc