Set the start bitrate to the delay-based BWE.

webrtc/modules/congestion_controller/congestion_controller.cc

Index: webrtc/modules/congestion_controller/congestion_controller.cc
diff --git a/webrtc/modules/congestion_controller/congestion_controller.cc b/webrtc/modules/congestion_controller/congestion_controller.cc
index 94b3d8c6da98bbaee3a070e8e9f2421044a758b9..1fd63a43b0a63d631e83af120a87bab4d6cbb6ce 100644
--- a/webrtc/modules/congestion_controller/congestion_controller.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller.cc
@@ -229,6 +229,7 @@ void CongestionController::SetBweBitrates(int min_bitrate_bps,
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
   min_bitrate_bps_ = min_bitrate_bps;
+  transport_feedback_adapter_.SetStartBitrate(start_bitrate_bps);
   transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps_);
   MaybeTriggerOnNetworkChanged();
 }
@@ -249,6 +250,7 @@ void CongestionController::ResetBweAndBitrates(int bitrate_bps,
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
 
   transport_feedback_adapter_.InitBwe();
+  transport_feedback_adapter_.SetStartBitrate(bitrate_bps);
   transport_feedback_adapter_.SetMinBitrate(min_bitrate_bps);
   // TODO(holmer): Trigger a new probe once mid-call probing is implemented.
   MaybeTriggerOnNetworkChanged();