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

webrtc/pc/webrtcsession.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 1877 matching lines @@
         this, &WebRtcSession::OnDtlsSrtpSetupFailure);
     rtp_data_channel_->SignalSentPacket.connect(this,
                                                 &WebRtcSession::OnSentPacket_w);
   }
 
   SignalDataChannelCreated();
 
   return true;
 }
 
+Call::Stats WebRtcSession::GetCallStats() {
+  return call_->GetStats();

[hbos, 2017/05/09 12:48:14]

I suspect this is not safe? call_ is a raw pointer, typically accessed by
call_w() which DCHECKs to be on the worker thread and might modify it. Can you
add a DCHECK or invoke on worker?

[holmer, 2017/05/30 14:44:29]

As discussed offline, I have no added thread checkers and introduced a
GetCallStats_s() method to be used in statscollector.cc.

+}
+
 std::unique_ptr<SessionStats> WebRtcSession::GetStats_n(
     const ChannelNamePairs& channel_name_pairs) {
   RTC_DCHECK(network_thread()->IsCurrent());
   std::unique_ptr<SessionStats> session_stats(new SessionStats());
   for (const auto channel_name_pair : { &channel_name_pairs.voice,
                                         &channel_name_pairs.video,
                                         &channel_name_pairs.data }) {
     if (*channel_name_pair) {
       cricket::TransportStats transport_stats;
       if (!transport_controller_->GetStats((*channel_name_pair)->transport_name,
@@ skipping 480 matching lines @@
       (rtp_data_channel_->rtcp_dtls_transport() != nullptr);
   channel_manager_->DestroyRtpDataChannel(rtp_data_channel_.release());
   transport_controller_->DestroyDtlsTransport(
       transport_name, cricket::ICE_CANDIDATE_COMPONENT_RTP);
   if (need_to_delete_rtcp) {
     transport_controller_->DestroyDtlsTransport(
         transport_name, cricket::ICE_CANDIDATE_COMPONENT_RTCP);
   }
 }
 }  // namespace webrtc