Refactored incoming bitrate estimator.

webrtc/modules/congestion_controller/delay_based_bwe.h

Index: webrtc/modules/congestion_controller/delay_based_bwe.h
diff --git a/webrtc/modules/congestion_controller/delay_based_bwe.h b/webrtc/modules/congestion_controller/delay_based_bwe.h
index eccd73ac4d49f7daea6b7fd1ae7366b6e6089d50..a1fc49cab2944959fa6a14c336bb1a2df981a173 100644
--- a/webrtc/modules/congestion_controller/delay_based_bwe.h
+++ b/webrtc/modules/congestion_controller/delay_based_bwe.h
@@ -18,6 +18,7 @@
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/thread_checker.h"
+#include "webrtc/modules/congestion_controller/incoming_bitrate_estimator.h"
 #include "webrtc/modules/congestion_controller/median_slope_estimator.h"
 #include "webrtc/modules/congestion_controller/probe_bitrate_estimator.h"
 #include "webrtc/modules/congestion_controller/trendline_estimator.h"
@@ -44,7 +45,9 @@ class DelayBasedBwe {
     uint32_t target_bitrate_bps;
   };
 
-  DelayBasedBwe(RtcEventLog* event_log, const Clock* clock);
+  DelayBasedBwe(RtcEventLog* event_log,
+                IncomingBitrateEstimator* const receiver_incoming_bitrate,
+                const Clock* clock);
   virtual ~DelayBasedBwe();
 
   Result IncomingPacketFeedbackVector(
@@ -57,26 +60,6 @@ class DelayBasedBwe {
   int64_t GetExpectedBwePeriodMs() 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 {
-   public:
-    BitrateEstimator();
-    void Update(int64_t now_ms, int bytes);
-    rtc::Optional<uint32_t> bitrate_bps() const;
-
-   private:
-    float UpdateWindow(int64_t now_ms, int bytes, int rate_window_ms);
-    int sum_;
-    int64_t current_win_ms_;
-    int64_t prev_time_ms_;
-    float bitrate_estimate_;
-    float bitrate_estimate_var_;
-  };
-
   void IncomingPacketFeedback(const PacketFeedback& packet_feedback);
   Result OnLongFeedbackDelay(int64_t arrival_time_ms);
 
@@ -94,7 +77,7 @@ class DelayBasedBwe {
   std::unique_ptr<InterArrival> inter_arrival_;
   std::unique_ptr<TrendlineEstimator> trendline_estimator_;
   OveruseDetector detector_;
-  BitrateEstimator receiver_incoming_bitrate_;
+  IncomingBitrateEstimator* const receiver_incoming_bitrate_;
   int64_t last_seen_packet_ms_;
   bool uma_recorded_;
   AimdRateControl rate_control_;