Fix crash on multiple feedback messages are received on old transport.

webrtc/modules/congestion_controller/congestion_controller_unittest.cc

 /*
  *  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 217 matching lines @@
   // the minimum default bitrate kMinBitrateBps.
   EXPECT_CALL(
       observer_,
       OnNetworkChanged(congestion_controller::GetMinBitrateBps(), _, _, _));
   EXPECT_CALL(*pacer_,
               SetEstimatedBitrate(congestion_controller::GetMinBitrateBps()));
   route.local_network_id = 2;
   controller_->OnNetworkRouteChanged(route, -1, -1, -1);
 }
 
+TEST_F(CongestionControllerTest, OldFeedback) {
+  int new_bitrate = 200000;
+  testing::Mock::VerifyAndClearExpectations(pacer_);
+  EXPECT_CALL(observer_, OnNetworkChanged(new_bitrate, _, _, _));
+  EXPECT_CALL(*pacer_, SetEstimatedBitrate(new_bitrate));
+
+  // Send a few packets on the first network route.
+  std::vector<PacketFeedback> packets;
+  packets.push_back(PacketFeedback(0, 0, 0, 1500, kPacingInfo0));
+  packets.push_back(PacketFeedback(10, 10, 1, 1500, kPacingInfo0));
+  packets.push_back(PacketFeedback(20, 20, 2, 1500, kPacingInfo0));
+  packets.push_back(PacketFeedback(30, 30, 3, 1500, kPacingInfo1));
+  packets.push_back(PacketFeedback(40, 40, 4, 1500, kPacingInfo1));
+
+  for (const PacketFeedback& packet : packets)
+    OnSentPacket(packet);
+
+  // Change route and then insert a number of feedback packets.
+  rtc::NetworkRoute route;
+  route.local_network_id = 1;
+  controller_->OnNetworkRouteChanged(route, new_bitrate, -1, -1);
+
+  for (const PacketFeedback& packet : packets) {
+    rtcp::TransportFeedback feedback;
+    feedback.SetBase(packet.sequence_number, packet.arrival_time_ms * 1000);
+
+    EXPECT_TRUE(feedback.AddReceivedPacket(packet.sequence_number,
+                                           packet.arrival_time_ms * 1000));
+    feedback.Build();
+    controller_->OnTransportFeedback(feedback);
+  }
+
+  // If the bitrate is reset to -1, the new starting bitrate will be
+  // the minimum default bitrate kMinBitrateBps.
+  EXPECT_CALL(
+      observer_,
+      OnNetworkChanged(congestion_controller::GetMinBitrateBps(), _, _, _));
+  EXPECT_CALL(*pacer_,
+              SetEstimatedBitrate(congestion_controller::GetMinBitrateBps()));
+  route.local_network_id = 2;
+  controller_->OnNetworkRouteChanged(route, -1, -1, -1);
+}
+
 TEST_F(CongestionControllerTest,
        SignalNetworkStateAndQueueIsFullAndEstimateChange) {
   // Send queue is full
   EXPECT_CALL(*pacer_, ExpectedQueueTimeMs())
       .WillRepeatedly(Return(PacedSender::kMaxQueueLengthMs + 1));
   EXPECT_CALL(observer_, OnNetworkChanged(0, _, _, _));
   controller_->Process();
 
   // Queue is full and network is down. Expect no bitrate change.
   controller_->SignalNetworkState(kNetworkDown);
@@ skipping 188 matching lines @@
   ASSERT_TRUE(target_bitrate_bps_);
 
   // Repeat, but this time with a building delay, and make sure that the
   // estimation is adjusted downwards.
   uint32_t bitrate_before_delay = *target_bitrate_bps_;
   PacketTransmissionAndFeedbackBlock(&seq_num, kRunTimeMs, 50);
   EXPECT_LT(*target_bitrate_bps_, bitrate_before_delay);
 }
 }  // namespace test
 }  // namespace webrtc