Add a 'remote' property to MediaSourceInterface. Also adding an implementation to the relevant sour…

talk/app/webrtc/remoteaudiosource.cc

Index: talk/app/webrtc/remoteaudiosource.cc
diff --git a/talk/app/webrtc/remoteaudiosource.cc b/talk/app/webrtc/remoteaudiosource.cc
index a35f0bb787f3129c9655ecf737d575fe8689c2b8..e904dd91925e48654832a5bb769f2e971c8b513e 100644
--- a/talk/app/webrtc/remoteaudiosource.cc
+++ b/talk/app/webrtc/remoteaudiosource.cc
@@ -106,6 +106,11 @@ MediaSourceInterface::SourceState RemoteAudioSource::state() const {
   return state_;
 }
 
+bool RemoteAudioSource::remote() const {
+  RTC_DCHECK(main_thread_->IsCurrent());
+  return true;
+}
+
 void RemoteAudioSource::SetVolume(double volume) {
   RTC_DCHECK(volume >= 0 && volume <= 10);
   for (auto* observer : audio_observers_)