Set the start bitrate to the delay-based BWE.

webrtc/modules/congestion_controller/delay_based_bwe.h

 /*
  *  Copyright (c) 2016 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 34 matching lines @@
   };
 
   explicit DelayBasedBwe(Clock* clock);
   virtual ~DelayBasedBwe() {}
 
   Result IncomingPacketFeedbackVector(
       const std::vector<PacketInfo>& packet_feedback_vector);
   void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms);
   bool LatestEstimate(std::vector<uint32_t>* ssrcs,
                       uint32_t* bitrate_bps) const;
+  void SetStartBitrate(int start_bitrate_bps);
   void SetMinBitrate(int min_bitrate_bps);
   int64_t GetProbingIntervalMs() const;
 
  private:
   // Computes a bayesian estimate of the throughput given acks containing
   // the arrival time and payload size. Samples which are far from the current
   // estimate or are based on few packets are given a smaller weight, as they
   // are considered to be more likely to have been caused by, e.g., delay spikes
   // unrelated to congestion.
   class BitrateEstimator {
@@ skipping 42 matching lines @@
   ProbingIntervalEstimator probing_interval_estimator_;
   size_t median_slope_window_size_;
   double median_slope_threshold_gain_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(DelayBasedBwe);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_H_