Add a new overuse estimator for the delay based BWE behind experiment.

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.
  */
 
 #ifndef WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_H_
 #define WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_H_
 
 #include <memory>
 #include <utility>
 #include <vector>
 
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/rate_statistics.h"
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/modules/congestion_controller/probe_bitrate_estimator.h"
+#include "webrtc/modules/congestion_controller/trendline_estimator.h"
 #include "webrtc/modules/remote_bitrate_estimator/aimd_rate_control.h"
 #include "webrtc/modules/remote_bitrate_estimator/include/remote_bitrate_estimator.h"
 #include "webrtc/modules/remote_bitrate_estimator/inter_arrival.h"
 #include "webrtc/modules/remote_bitrate_estimator/overuse_detector.h"
 #include "webrtc/modules/remote_bitrate_estimator/overuse_estimator.h"
 
 namespace webrtc {
 
 class DelayBasedBwe {
  public:
@@ skipping 45 matching lines @@
   // Updates the current remote rate estimate and returns true if a valid
   // estimate exists.
   bool UpdateEstimate(int64_t packet_arrival_time_ms,
                       int64_t now_ms,
                       rtc::Optional<uint32_t> acked_bitrate_bps,
                       uint32_t* target_bitrate_bps);
 
   rtc::ThreadChecker network_thread_;
   Clock* const clock_;
   std::unique_ptr<InterArrival> inter_arrival_;
-  std::unique_ptr<OveruseEstimator> estimator_;
+  std::unique_ptr<OveruseEstimator> kalman_estimator_;
+  std::unique_ptr<TrendlineEstimator> trendline_estimator_;
   OveruseDetector detector_;
   BitrateEstimator receiver_incoming_bitrate_;
   int64_t last_update_ms_;
   int64_t last_seen_packet_ms_;
   bool uma_recorded_;
   AimdRateControl rate_control_;
   ProbeBitrateEstimator probe_bitrate_estimator_;
+  size_t trendline_window_size_;
+  double trendline_smoothing_coeff_;
+  double trendline_threshold_gain_;
+  const bool in_trendline_experiment_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(DelayBasedBwe);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_H_