Wire up BWE stats through WebrtcSession so that they are filled in both for audio and video calls.

webrtc/pc/channel.h

Index: webrtc/pc/channel.h
diff --git a/webrtc/pc/channel.h b/webrtc/pc/channel.h
index 48259e5fd9d7732b94c4deaa817265edf5b85b59..17a83a13bc902715405cd30f5b6f238978242a17 100644
--- a/webrtc/pc/channel.h
+++ b/webrtc/pc/channel.h
@@ -350,11 +350,10 @@ class BaseChannel
   virtual void OnConnectionMonitorUpdate(ConnectionMonitor* monitor,
       const std::vector<ConnectionInfo>& infos) = 0;
 
-  // Helper function for invoking bool-returning methods on the worker thread.
-  template <class FunctorT>
-  bool InvokeOnWorker(const rtc::Location& posted_from,
-                      const FunctorT& functor) {
-    return worker_thread_->Invoke<bool>(posted_from, functor);
+  // Helper function template for invoking methods on the worker thread.
+  template <class T, class FunctorT>
+  T InvokeOnWorker(const rtc::Location& posted_from, const FunctorT& functor) {
+    return worker_thread_->Invoke<T>(posted_from, functor);
   }
 
  private:
@@ -554,6 +553,7 @@ class VideoChannel : public BaseChannel {
 
   bool SetSink(uint32_t ssrc,
                rtc::VideoSinkInterface<webrtc::VideoFrame>* sink);
+  void FillBitrateInfo(BandwidthEstimationInfo* bwe_info);
   // Get statistics about the current media session.
   bool GetStats(VideoMediaInfo* stats);