Added implementation of three classes in BBR,with unit-tests.

webrtc/modules/remote_bitrate_estimator/test/estimators/bbr.h

 /*
  *  Copyright (c) 2017 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 41 matching lines @@
   void GiveFeedback(const FeedbackPacket& feedback) override;
   int64_t TimeUntilNextProcess() override;
   void Process() override;
 
  private:
   void EnterStartup();
   bool UpdateBandwidthAndMinRtt();
   void TryExitingStartup();
   void TryExitingDrain(int64_t now_ms);
   void EnterProbeBw(int64_t now_ms);
-  void EnterProbeRtt(int64_t now_ms);
   void TryUpdatingCyclePhase(int64_t now_ms);
-  void TryEnteringProbeRtt(int64_t now_ms);
-  void TryExitingProbeRtt(int64_t now_ms);
+  void TryEnteringProbeRtt(int64_t now_ms, bool min_rtt_expired);
+  void TryExitingProbeRtt(int64_t now_ms, int64_t round, bool min_rtt_expired);
+  size_t TargetCongestionWindow(float gain);
   Clock* const clock_;
   Mode mode_;
   std::unique_ptr<MaxBandwidthFilter> max_bandwidth_filter_;
+  std::unique_ptr<MinRttFilter> min_rtt_filter_;
+  std::unique_ptr<CongestionWindow> congestion_window_;
   uint64_t round_count_;
   uint64_t last_packet_sent_;
   uint64_t round_trip_end_;
   float pacing_gain_;
   float congestion_window_gain_;
 
   // If optimal bandwidth has been discovered and reached, (for example after
   // Startup mode) set this variable to true.
   bool full_bandwidth_reached_;
+  int64_t cycle_start_time_ms_;
+  int64_t cycle_index_;
+  size_t prior_in_flight_;
+  int64_t probe_rtt_start_time_ms_;
+  int64_t minimum_congestion_window_start_time_ms_;
+  int64_t minimum_congestion_window_start_round_;
 };
 
 class BbrBweReceiver : public BweReceiver {
  public:
   explicit BbrBweReceiver(int flow_id);
   virtual ~BbrBweReceiver();
   void ReceivePacket(int64_t arrival_time_ms,
                      const MediaPacket& media_packet) override;
   FeedbackPacket* GetFeedback(int64_t now_ms) override;
 
  private:
   SimulatedClock clock_;
 };
 }  // namespace bwe
 }  // namespace testing
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_ESTIMATORS_BBR_H_