Support REMB in combination with send-side BWE.

webrtc/modules/bitrate_controller/bitrate_controller_unittest.cc

 /*
  *  Copyright (c) 2012 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 @@
   report_blocks.push_back(CreateReportBlock(1, 2, 0, 101));
   bandwidth_observer_->OnReceivedRtcpReceiverReport(report_blocks, 50, time_ms);
   EXPECT_EQ(300000, bitrate_observer_.last_bitrate_);
   time_ms += 1000;
 
   report_blocks.clear();
   report_blocks.push_back(CreateReportBlock(1, 2, 0, 141));
   bandwidth_observer_->OnReceivedRtcpReceiverReport(report_blocks, 50, time_ms);
   EXPECT_EQ(300000, bitrate_observer_.last_bitrate_);
 
-  // Test that a low REMB trigger immediately.
+  // Test that a low delay-based estimate limits the combined estimate.
+  controller_->UpdateDelayBasedEstimate(280000);
+  EXPECT_EQ(280000, bitrate_observer_.last_bitrate_);
+
+  // Test that a low REMB limits the combined estimate.
   bandwidth_observer_->OnReceivedEstimatedBitrate(250000);
   EXPECT_EQ(250000, bitrate_observer_.last_bitrate_);
   EXPECT_EQ(0, bitrate_observer_.last_fraction_loss_);
   EXPECT_EQ(50, bitrate_observer_.last_rtt_);
 
   bandwidth_observer_->OnReceivedEstimatedBitrate(1000);
-  EXPECT_EQ(100000, bitrate_observer_.last_bitrate_);  // Min cap.
+  EXPECT_EQ(100000, bitrate_observer_.last_bitrate_);
 }
 
 TEST_F(BitrateControllerTest, OneBitrateObserverTwoRtcpObservers) {
   // REMBs during the first 2 seconds apply immediately.
   int64_t time_ms = 1;
   webrtc::ReportBlockList report_blocks;
   report_blocks.push_back(CreateReportBlock(1, 2, 0, 1));
   bandwidth_observer_->OnReceivedRtcpReceiverReport(report_blocks, 50, time_ms);
   report_blocks.clear();
   time_ms += 500;
@@ skipping 205 matching lines @@
   EXPECT_EQ(120000, bitrate_observer_.last_bitrate_);
   controller_->SetReservedBitrate(50000);
   bandwidth_observer_->OnReceivedEstimatedBitrate(120000);
   // Limited by min bitrate.
   EXPECT_EQ(100000, bitrate_observer_.last_bitrate_);
 
   controller_->SetReservedBitrate(10000);
   bandwidth_observer_->OnReceivedEstimatedBitrate(1);
   EXPECT_EQ(100000, bitrate_observer_.last_bitrate_);
 }