Moving MediaStreamSignaling logic into PeerConnection.

talk/app/webrtc/statscollector.h

Index: talk/app/webrtc/statscollector.h
diff --git a/talk/app/webrtc/statscollector.h b/talk/app/webrtc/statscollector.h
index 99130a3f0133791ebf9d9e89119edb9c0b78ee7b..7dec9296b08038be50f1761129693d4942a3403d 100644
--- a/talk/app/webrtc/statscollector.h
+++ b/talk/app/webrtc/statscollector.h
@@ -43,6 +43,8 @@
 
 namespace webrtc {
 
+class PeerConnection;
+
 // Conversion function to convert candidate type string to the corresponding one
 // from  enum RTCStatsIceCandidateType.
 const char* IceCandidateTypeToStatsType(const std::string& candidate_type);
@@ -57,9 +59,9 @@ typedef std::map<std::string, StatsReport*> TrackIdMap;
 
 class StatsCollector {
  public:
-  // The caller is responsible for ensuring that the session outlives the
-  // StatsCollector instance.
-  explicit StatsCollector(WebRtcSession* session);
+  // The caller is responsible for ensuring that the pc and session
+  // outlive the StatsCollector instance.
+  explicit StatsCollector(PeerConnection* pc, WebRtcSession* session);

[Taylor Brandstetter, 2015/10/07 00:26:19]

I don't really like passing the StatsCollector a PeerConnection pointer, but we
already pass it a WebRtcSession pointer... And later WebRtcSession will become
PeerConnection. Maybe in the future we should define a new interface that
StatsCollector depends on, distinct from PeerConnection and
PeerConnectionInterface?

[pthatcher1, 2015/10/07 02:50:51]

It makes sense to pass a PeerConnection in.  It's passing both a pc and a
session that's lame.  

Could we just make PeerConnection implement all of the methods that
StatsCollector needs from WebRtcSession by calling down to WebRtcSession inside
of it?  Then this test won't need to change again when WebRtcSession and
PeerConnection are merged.

[pthatcher1, 2015/10/08 22:05:36]

Or maybe pc_->session()?

[Taylor Brandstetter, 2015/10/09 19:54:09]

Done.

   virtual ~StatsCollector();
 
   // Adds a MediaStream with tracks that can be used as a |selector| in a call
@@ -148,7 +150,9 @@ class StatsCollector {
   // A collection for all of our stats reports.
   StatsCollection reports_;
   TrackIdMap track_ids_;
-  // Raw pointer to the session the statistics are gathered from.
+  // Raw pointers to the peer connection and session the statistics are
+  // gathered from.
+  PeerConnection* const pc_;
   WebRtcSession* const session_;
   double stats_gathering_started_;
   cricket::ProxyTransportMap proxy_to_transport_;