Fix crash when all acks in a feedback message arrive too late.

webrtc/modules/congestion_controller/delay_based_bwe_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.
  */
 
 #include "webrtc/test/gtest.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/pacing/paced_sender.h"
 #include "webrtc/modules/congestion_controller/delay_based_bwe.h"
 #include "webrtc/modules/congestion_controller/delay_based_bwe_unittest_helper.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/test/field_trial.h"
 
 namespace webrtc {
 
 namespace {
 constexpr int kNumProbesCluster0 = 5;
 constexpr int kNumProbesCluster1 = 8;
 const PacedPacketInfo kPacingInfo0(0, kNumProbesCluster0, 2000);
 const PacedPacketInfo kPacingInfo1(1, kNumProbesCluster1, 4000);
 }  // namespace
 
+TEST_F(DelayBasedBweTest, NoCrashEmptyFeedback) {
+  std::vector<PacketFeedback> packet_feedback_vector;
+  bitrate_estimator_->IncomingPacketFeedbackVector(packet_feedback_vector);
+}
+
+TEST_F(DelayBasedBweTest, NoCrashOnlyLostFeedback) {
+  std::vector<PacketFeedback> packet_feedback_vector;
+  packet_feedback_vector.push_back(
+      PacketFeedback(-1, -1, 0, 1500, PacedPacketInfo()));
+  packet_feedback_vector.push_back(
+      PacketFeedback(-1, -1, 1, 1500, PacedPacketInfo()));
+  bitrate_estimator_->IncomingPacketFeedbackVector(packet_feedback_vector);
+}
+
 TEST_F(DelayBasedBweTest, ProbeDetection) {
   int64_t now_ms = clock_.TimeInMilliseconds();
   uint16_t seq_num = 0;
 
   // First burst sent at 8 * 1000 / 10 = 800 kbps.
   for (int i = 0; i < kNumProbesCluster0; ++i) {
     clock_.AdvanceTimeMilliseconds(10);
     now_ms = clock_.TimeInMilliseconds();
     IncomingFeedback(now_ms, now_ms, seq_num++, 1000, kPacingInfo0);
   }
@@ skipping 126 matching lines @@
 
 TEST_F(DelayBasedBweTest, TestLongTimeoutAndWrap) {
   // Simulate a client leaving and rejoining the call after some multiple of
   // 64 seconds later. This will cause a zero difference in abs send times due
   // to the wrap, but a big difference in arrival time, if streams aren't
   // properly timed out.
   TestWrappingHelper(10 * 64);
 }
 
 }  // namespace webrtc