Test and fix for huge bwe drop after alr state.

webrtc/modules/congestion_controller/acknowledge_bitrate_estimator.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.
- */
-
-#ifndef WEBRTC_MODULES_CONGESTION_CONTROLLER_ACKNOWLEDGE_BITRATE_ESTIMATOR_H_
-#define WEBRTC_MODULES_CONGESTION_CONTROLLER_ACKNOWLEDGE_BITRATE_ESTIMATOR_H_
-
-#include <vector>
-
-#include "webrtc/base/optional.h"
-
-namespace webrtc {
-
-struct PacketFeedback;
-
-// 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 AcknowledgedBitrateEstimator {
- public:
-  AcknowledgedBitrateEstimator();
-
-  void IncomingPacketFeedbackVector(
-      const std::vector<PacketFeedback>& packet_feedback_vector);
-  rtc::Optional<uint32_t> bitrate_bps() const;
-
- private:
-  void Update(int64_t now_ms, int bytes);
-  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_;
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_ACKNOWLEDGE_BITRATE_ESTIMATOR_H_