Probing: Add support for exponential startup probing

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 88bc9071364ea8f169f957cc9e9d38aa35f3f59e..e6f54b20d724283822065f8ae168621bdcc0d10a 100644
--- a/webrtc/modules/congestion_controller/congestion_controller.cc
+++ b/webrtc/modules/congestion_controller/congestion_controller.cc
@@ -169,7 +169,7 @@ CongestionController::CongestionController(
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
-      transport_feedback_adapter_(bitrate_controller_.get(), clock_),
+      transport_feedback_adapter_(clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
@@ -198,7 +198,7 @@ CongestionController::CongestionController(
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       remote_estimator_proxy_(clock_, packet_router_.get()),
-      transport_feedback_adapter_(bitrate_controller_.get(), clock_),
+      transport_feedback_adapter_(clock_),
       min_bitrate_bps_(RemoteBitrateEstimator::kDefaultMinBitrateBps),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
@@ -211,7 +211,7 @@ CongestionController::~CongestionController() {}
 
 void CongestionController::Init() {
   transport_feedback_adapter_.SetBitrateEstimator(
-      new DelayBasedBwe(&transport_feedback_adapter_, clock_));
+      new DelayBasedBwe(this, clock_));
   transport_feedback_adapter_.GetBitrateEstimator()->SetMinBitrate(
       min_bitrate_bps_);
 }
@@ -246,8 +246,7 @@ void CongestionController::ResetBweAndBitrates(int bitrate_bps,
   if (remote_bitrate_estimator_)
     remote_bitrate_estimator_->SetMinBitrate(min_bitrate_bps);
 
-  RemoteBitrateEstimator* rbe = new DelayBasedBwe(
-      &transport_feedback_adapter_, clock_);
+  RemoteBitrateEstimator* rbe = new DelayBasedBwe(this, clock_);
   transport_feedback_adapter_.SetBitrateEstimator(rbe);
   rbe->SetMinBitrate(min_bitrate_bps);
   // TODO(holmer): Trigger a new probe once mid-call probing is implemented.
@@ -306,6 +305,14 @@ void CongestionController::OnSentPacket(const rtc::SentPacket& sent_packet) {
                                            sent_packet.send_time_ms);
 }
 
+void CongestionController::OnDelayBasedBweChanged(int bitrate_bps) {
+  bitrate_controller_->UpdateDelayBasedEstimate(bitrate_bps);
+}
+
+bool CongestionController::IsExpectingProbingResults() {
+  return pacer_->IsExpectingProbingResults();
+}
+
 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);