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

webrtc/media/base/fakemediaengine.h

 /*
  *  Copyright (c) 2004 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 586 matching lines @@
     sinks_[sp.first_ssrc()] = NULL;
     return true;
   }
   bool RemoveRecvStream(uint32_t ssrc) override {
     if (!RtpHelper<VideoMediaChannel>::RemoveRecvStream(ssrc))
       return false;
     sinks_.erase(ssrc);
     return true;
   }
 
+  void FillBitrateInfo(BandwidthEstimationInfo* bwe_info) override {}
   bool GetStats(VideoMediaInfo* info) override { return false; }
 
  private:
   bool SetRecvCodecs(const std::vector<VideoCodec>& codecs) {
     if (fail_set_recv_codecs()) {
       // Fake the failure in SetRecvCodecs.
       return false;
     }
     recv_codecs_ = codecs;
     return true;
@@ skipping 348 matching lines @@
   virtual const std::vector<DataCodec>& data_codecs() { return data_codecs_; }
 
  private:
   std::vector<FakeDataMediaChannel*> channels_;
   std::vector<DataCodec> data_codecs_;
 };
 
 }  // namespace cricket
 
 #endif  // WEBRTC_MEDIA_BASE_FAKEMEDIAENGINE_H_