fix packet conservation to remove packets from recovery window when they are lost. Protected by FL…

net/quic/core/congestion_control/bbr_sender_test.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/congestion_control/bbr_sender.h"
 
 #include <algorithm>
 #include <map>
 #include <memory>
 
@@ skipping 79 matching lines @@
                             /*connection_id=*/GetPeerInMemoryConnectionId(43)),
         receiver_multiplexer_("Receiver multiplexer",
                               {&receiver_, &competing_receiver_}) {
     // These will be changed by the appropriate tests as necessary.
     FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = false;
     FLAGS_quic_reloadable_flag_quic_bbr_slow_recent_delivery = false;
     FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = false;
     // TODO(ianswett): Determine why tests become flaky with CWND based on SRTT.
     FLAGS_quic_reloadable_flag_quic_bbr_base_cwnd_on_srtt = false;
     FLAGS_quic_reloadable_flag_quic_bbr_extra_conservation = true;
-    FLAGS_quic_reloadable_flag_quic_bbr_fix_conservation = true;
+    FLAGS_quic_reloadable_flag_quic_bbr_fix_conservation2 = true;
     rtt_stats_ = bbr_sender_.connection()->sent_packet_manager().GetRttStats();
     sender_ = SetupBbrSender(&bbr_sender_);
 
     clock_ = simulator_.GetClock();
     simulator_.set_random_generator(&random_);
 
     uint64_t seed = QuicRandom::GetInstance()->RandUint64();
     random_.set_seed(seed);
     QUIC_LOG(INFO) << "BbrSenderTest simulator set up.  Seed: " << seed;
   }
@@ skipping 376 matching lines @@
   simulator_result = simulator_.RunUntilOrTimeout(
       [this]() {
         return sender_->ExportDebugState().recovery_state !=
                BbrSender::NOT_IN_RECOVERY;
       },
       timeout);
   ASSERT_TRUE(simulator_result);
   ASSERT_EQ(BbrSender::CONSERVATION,
             sender_->ExportDebugState().recovery_state);
 
-  const QuicByteCount cwnd_at_recovery_start = sender_->GetCongestionWindow();
   simulator_result = simulator_.RunUntilOrTimeout(
-      [this, cwnd_at_recovery_start]() {
-        // Ensure that the CWND never drops due to conservation.
-        if (sender_->GetCongestionWindow() < cwnd_at_recovery_start) {
-          return true;
-        }
+      [this]() {
         return sender_->ExportDebugState().recovery_state !=
                BbrSender::CONSERVATION;
       },
       timeout);
-  ASSERT_GE(sender_->GetCongestionWindow(), cwnd_at_recovery_start);
   ASSERT_TRUE(simulator_result);
   ASSERT_EQ(BbrSender::GROWTH, sender_->ExportDebugState().recovery_state);
 
   simulator_result = simulator_.RunUntilOrTimeout(
       [this]() {
         return sender_->ExportDebugState().recovery_state != BbrSender::GROWTH;
       },
       timeout);
 
   ASSERT_EQ(BbrSender::PROBE_BW, sender_->ExportDebugState().mode);
@@ skipping 299 matching lines @@
   sender_->ResumeConnectionState(params, false);
   EXPECT_EQ(kTestLinkBandwidth, sender_->ExportDebugState().max_bandwidth);
   EXPECT_EQ(kTestLinkBandwidth, sender_->BandwidthEstimate());
   ExpectApproxEq(kTestRtt, sender_->ExportDebugState().min_rtt, 0.01f);
 
   DriveOutOfStartup();
 }
 
 }  // namespace test
 }  // namespace net