Move congestion controller processing to the pacer thread.

webrtc/modules/congestion_controller/congestion_controller.cc

 /*
  *  Copyright (c) 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 309 matching lines @@
   transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id,
                                            sent_packet.send_time_ms);
 }
 
 void CongestionController::OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) {
   remote_bitrate_estimator_->OnRttUpdate(avg_rtt_ms, max_rtt_ms);
   transport_feedback_adapter_.OnRttUpdate(avg_rtt_ms, max_rtt_ms);
 }
 
 int64_t CongestionController::TimeUntilNextProcess() {
-  return std::min(bitrate_controller_->TimeUntilNextProcess(),
-                  remote_bitrate_estimator_->TimeUntilNextProcess());
+  return std::min({bitrate_controller_->TimeUntilNextProcess(),
+                   remote_bitrate_estimator_->TimeUntilNextProcess(),
+                   pacer_->TimeUntilNextProcess(),
+                   remote_estimator_proxy_.TimeUntilNextProcess()});
 }
 
 void CongestionController::Process() {
   bitrate_controller_->Process();
   remote_bitrate_estimator_->Process();
   probe_controller_->Process();
+  pacer_->Process();
+  remote_estimator_proxy_.Process();
   MaybeTriggerOnNetworkChanged();

[danilchap, 2017/01/16 17:09:39]

look like it is this function that SetEstimatedBitrate.
Does it make sense to put it before pacer_->Process(); // With a comment why.

[nisse-webrtc, 2017/01/17 07:42:39]

Reorder isn't enough, first call to MaybeTriggerOnNetworkChanged gets
|estimate_changed| == false, and hence doesn't call SetEstimatedBitrate.

So PacedSender::Process still needs the change to make calling
alr_detector_->OnBytesSent conditional on bytes_sent > 0, otherwise it crashes
in the AlrDetector DCHECK.

I'd be happy to reorder the calls anyway you like (I really don't know  if some
order makes more sense than any  other order), but it seems it doesn't by itself
solve the AlrDetector call order requirements.

[stefan-webrtc, 2017/01/17 07:59:54]

It might be a good idea to call MaybeTriggerOnNetworkChanged() before
probe_controller_->Process(), pacer_->Process() and
remote_estimator_proxy_.Process(), simply because they use the result of
MaybeTriggerOnNetworkChanged().

[nisse-webrtc, 2017/01/17 08:39:35]

Done.

 }
 
 void CongestionController::MaybeTriggerOnNetworkChanged() {
   // TODO(perkj): |observer_| can be nullptr if the ctor that accepts a
   // BitrateObserver is used. Remove this check once the ctor is removed.
   if (!observer_)
     return;
 
   uint32_t bitrate_bps;
   uint8_t fraction_loss;
@@ skipping 38 matching lines @@
 bool CongestionController::IsSendQueueFull() const {
   return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
 }
 
 bool CongestionController::IsNetworkDown() const {
   rtc::CritScope cs(&critsect_);
   return network_state_ == kNetworkDown;
 }
 
 }  // namespace webrtc