Support for remote audio into tracks

talk/app/webrtc/peerconnection.cc

Index: talk/app/webrtc/peerconnection.cc
diff --git a/talk/app/webrtc/peerconnection.cc b/talk/app/webrtc/peerconnection.cc
index f1ff4e6d36ee5d82ceedca1124ad3dbfa89b078b..459c74cbbe0261239ff42ba357fe037e2ad30c46 100644
--- a/talk/app/webrtc/peerconnection.cc
+++ b/talk/app/webrtc/peerconnection.cc
@@ -39,6 +39,7 @@
 #include "talk/app/webrtc/mediastreamproxy.h"
 #include "talk/app/webrtc/mediastreamtrackproxy.h"
 #include "talk/app/webrtc/remoteaudiosource.h"
+#include "talk/app/webrtc/remoteaudiotrack.h"
 #include "talk/app/webrtc/remotevideocapturer.h"
 #include "talk/app/webrtc/rtpreceiver.h"
 #include "talk/app/webrtc/rtpsender.h"
@@ -449,10 +450,12 @@ class RemoteMediaStreamFactory {
                                     MediaStream::Create(stream_label));
   }
 
-  AudioTrackInterface* AddAudioTrack(webrtc::MediaStreamInterface* stream,
+  AudioTrackInterface* AddAudioTrack(uint32_t ssrc,
+                                     AudioProviderInterface* provider,
+                                     webrtc::MediaStreamInterface* stream,
                                      const std::string& track_id) {
-    return AddTrack<AudioTrackInterface, AudioTrack, AudioTrackProxy>(
-        stream, track_id, RemoteAudioSource::Create().get());
+    return AddTrack<AudioTrackInterface, RemoteAudioTrack, AudioTrackProxy>(
+        stream, track_id, RemoteAudioSource::Create(ssrc, provider));
   }
 
   VideoTrackInterface* AddVideoTrack(webrtc::MediaStreamInterface* stream,
@@ -468,7 +471,7 @@ class RemoteMediaStreamFactory {
   template <typename TI, typename T, typename TP, typename S>
   TI* AddTrack(MediaStreamInterface* stream,
                const std::string& track_id,
-               S* source) {
+               const S& source) {
     rtc::scoped_refptr<TI> track(
         TP::Create(signaling_thread_, T::Create(track_id, source)));
     track->set_state(webrtc::MediaStreamTrackInterface::kLive);
@@ -1590,8 +1593,8 @@ void PeerConnection::OnRemoteTrackSeen(const std::string& stream_label,
   MediaStreamInterface* stream = remote_streams_->find(stream_label);
 
   if (media_type == cricket::MEDIA_TYPE_AUDIO) {
-    AudioTrackInterface* audio_track =
-        remote_stream_factory_->AddAudioTrack(stream, track_id);
+    AudioTrackInterface* audio_track = remote_stream_factory_->AddAudioTrack(
+        ssrc, session_.get(), stream, track_id);

[perkj_webrtc, 2015/12/10 12:24:05]

The remote track can outlive the session since the track is ref counted. Is that
a problem?

[tommi, 2015/12/10 22:37:25]

That should be handled in the remote track implementation.  When the session
goes away, the track clears its pointer to the session.  However, since you
pointed it out, there is probably a chance that we have a problem still. I'll
look at it but basically if we pass a session pointer here and do not use it in
order to get the OnClose notification, we could have a UAF.  In the other case,
we do handle the session going out of scope.

     CreateAudioReceiver(stream, audio_track, ssrc);
   } else if (media_type == cricket::MEDIA_TYPE_VIDEO) {
     VideoTrackInterface* video_track =