Use bayesian estimate of acked bitrate.

webrtc/modules/congestion_controller/delay_based_bwe_unittest_helper.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 144 matching lines @@
   void RateIncreaseRtpTimestampsTestHelper(int expected_iterations);
   void CapacityDropTestHelper(int number_of_streams,
                               bool wrap_time_stamp,
                               uint32_t expected_bitrate_drop_delta,
                               int64_t receiver_clock_offset_change_ms);
 
   static const uint32_t kDefaultSsrc;
 
   SimulatedClock clock_;  // Time at the receiver.
   test::TestBitrateObserver bitrate_observer_;
-  DelayBasedBwe bitrate_estimator_;
+  std::unique_ptr<DelayBasedBwe> bitrate_estimator_;
   std::unique_ptr<test::StreamGenerator> stream_generator_;
   int64_t arrival_time_offset_ms_;
+  bool first_update_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(DelayBasedBweTest);
 };
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_CONGESTION_CONTROLLER_DELAY_BASED_BWE_UNITTEST_HELPER_H_