Added a callback function OnAddTrack to PeerConnectionObserver

webrtc/api/peerconnection_unittest.cc

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 398 matching lines @@
             remote_stream->GetVideoTracks()[track_index]->id();
         if (fake_video_renderers_.find(id) != fake_video_renderers_.end()) {
           continue;
         }
         fake_video_renderers_[id].reset(new webrtc::FakeVideoTrackRenderer(
             remote_stream->GetVideoTracks()[track_index]));
       }
     }
   }
 
+  void OnAddTrack(
+      rtc::scoped_refptr<webrtc::RtpReceiverInterface> receiver,
+      std::vector<rtc::scoped_refptr<MediaStreamInterface>> streams) override {}
+
   void SetVideoConstraints(const webrtc::FakeConstraints& video_constraint) {
     video_constraints_ = video_constraint;
   }
 
   void AddMediaStream(bool audio, bool video) {
     std::string stream_label =
         kStreamLabelBase +
         rtc::ToString<int>(static_cast<int>(pc()->local_streams()->count()));
     rtc::scoped_refptr<MediaStreamInterface> stream =
         peer_connection_factory_->CreateLocalMediaStream(stream_label);
@@ skipping 2345 matching lines @@
   server.urls.push_back("turn:hostname2");
   servers.push_back(server);
   EXPECT_TRUE(webrtc::ParseIceServers(servers, &stun_servers_, &turn_servers_));
   EXPECT_EQ(2U, turn_servers_.size());
   EXPECT_NE(turn_servers_[0].priority, turn_servers_[1].priority);
 }
 
 #endif // if !defined(THREAD_SANITIZER)
 
 }  // namespace