Update the BWE when the network route changes.

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 194 matching lines @@
 
 CongestionController::~CongestionController() {}
 
 void CongestionController::Init() {
   transport_feedback_adapter_.SetBitrateEstimator(
       new RemoteBitrateEstimatorAbsSendTime(&transport_feedback_adapter_));
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
 }
 
+void CongestionController::ClampBitrates(int* bitrate_bps,

[stefan-webrtc, 2016/05/30 06:47:03]

Seems like this can be a static function within this file only as it doesn't
access any members of the class. Move it to the top of the file too.

[honghaiz3, 2016/05/31 16:58:03]

Done.

+                                         int* min_bitrate_bps,
+                                         int* max_bitrate_bps) {
+  // TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
+  // and that we don't try to set the min bitrate to 0 from any applications.
+  // The congestion controller should allow a min bitrate of 0.
+  const int kMinBitrateBps = 10000;
+  if (*min_bitrate_bps < kMinBitrateBps)
+    *min_bitrate_bps = kMinBitrateBps;
+  if (*max_bitrate_bps > 0)
+    *max_bitrate_bps = std::max(*min_bitrate_bps, *max_bitrate_bps);
+  if (*bitrate_bps > 0)
+    *bitrate_bps = std::max(*min_bitrate_bps, *bitrate_bps);
+}
 
 void CongestionController::SetBweBitrates(int min_bitrate_bps,
                                           int start_bitrate_bps,
                                           int max_bitrate_bps) {
-  // TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
-  // and that we don't try to set the min bitrate to 0 from any applications.
-  // The congestion controller should allow a min bitrate of 0.
-  const int kMinBitrateBps = 10000;
-  if (min_bitrate_bps < kMinBitrateBps)
-    min_bitrate_bps = kMinBitrateBps;
-  if (max_bitrate_bps > 0)
-    max_bitrate_bps = std::max(min_bitrate_bps, max_bitrate_bps);
-  if (start_bitrate_bps > 0)
-    start_bitrate_bps = std::max(min_bitrate_bps, start_bitrate_bps);
-
+  ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
   bitrate_controller_->SetBitrates(start_bitrate_bps,
                                    min_bitrate_bps,
                                    max_bitrate_bps);
 
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
   min_bitrate_bps_ = min_bitrate_bps;
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
   MaybeTriggerOnNetworkChanged();
 }
 
+void CongestionController::ResetBweBitrates(int bitrate_bps,

[stefan-webrtc, 2016/05/30 06:47:03]

ResetBitrates() or maybe ResetBwe() to make it clear that not only bitrates are
reset, also the BWE state.

[honghaiz3, 2016/05/31 16:58:03]

Based on your comments, will it be clearer to use ResetBweAndBitrates?

[stefan-webrtc, 2016/05/31 17:27:49]

That works

+                                            int min_bitrate_bps,
+                                            int max_bitrate_bps) {
+  ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
+  bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
+                                     max_bitrate_bps);
+  min_bitrate_bps_ = min_bitrate_bps;
+  if (remote_bitrate_estimator_) {

[stefan-webrtc, 2016/05/30 06:47:03]

Remove {}

[honghaiz3, 2016/05/31 16:58:03]

Done.

+    remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
+  }
+
+  RemoteBitrateEstimator* rbe =
+      new RemoteBitrateEstimatorAbsSendTime(&transport_feedback_adapter_);
+  transport_feedback_adapter_.SetBitrateEstimator(rbe);

[stefan-webrtc, 2016/05/30 06:47:03]

Will the previous rbe be deleted?

[honghaiz3, 2016/05/31 16:58:03]

Yes, the bitrate_estimator_ is a unique_ptr. 

+  rbe->SetMinBitrate(min_bitrate_bps);
+

[stefan-webrtc, 2016/05/30 06:47:03]

Could you add a TODO which says "TODO(holmer): Trigger a new probe once mid-call
probing is implemented."? 

[honghaiz3, 2016/05/31 16:58:03]

Done.

+  MaybeTriggerOnNetworkChanged();
+}
+
 BitrateController* CongestionController::GetBitrateController() const {
   return bitrate_controller_.get();
 }
 
 RemoteBitrateEstimator* CongestionController::GetRemoteBitrateEstimator(
     bool send_side_bwe) {
   if (send_side_bwe) {
     return &remote_estimator_proxy_;
   } else {
     return remote_bitrate_estimator_.get();
@@ skipping 87 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