Fixing issue with default stream upon setting 2nd remote description.

talk/app/webrtc/peerconnection.h

Index: talk/app/webrtc/peerconnection.h
diff --git a/talk/app/webrtc/peerconnection.h b/talk/app/webrtc/peerconnection.h
index cd6f67121f2d32384bbda7889c804134023d36b3..2fd14d738cdb9d21d1ba049f2cd14da52d332fe8 100644
--- a/talk/app/webrtc/peerconnection.h
+++ b/talk/app/webrtc/peerconnection.h
@@ -158,6 +158,10 @@ class PeerConnection : public PeerConnectionInterface,
               const std::string track_id,
               uint32_t ssrc)
         : stream_label(stream_label), track_id(track_id), ssrc(ssrc) {}
+    bool operator==(const TrackInfo& other) {
+      return this->stream_label == other.stream_label &&
+             this->track_id == other.track_id && this->ssrc == other.ssrc;
+    }
     std::string stream_label;
     std::string track_id;
     uint32_t ssrc;
@@ -279,6 +283,7 @@ class PeerConnection : public PeerConnectionInterface,
   // exist.
   void UpdateEndedRemoteMediaStreams();
 
+  void MaybeRemoveDefaultTracks();
   void MaybeCreateDefaultStream();
 
   // Set the MediaStreamTrackInterface::TrackState to |kEnded| on all remote