Tweak BBR tests with the keep sending flag enabled to consistently pass unit tests.

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 322 matching lines @@
             sender_->ExportDebugState().max_bandwidth);
   // TODO(ianswett): Tighten this bound once we understand why BBR is
   // overestimating bandwidth with aggregation. b/36022633
   EXPECT_GE(kTestLinkBandwidth * 1.5f,
             sender_->ExportDebugState().max_bandwidth);
   // TODO(ianswett): Expect 0 packets are lost once BBR no longer measures
   // bandwidth higher than the link rate.
   EXPECT_FALSE(sender_->ExportDebugState().last_sample_is_app_limited);
   // The margin here is high, because the aggregation greatly increases
   // smoothed rtt.
-  EXPECT_GE(kTestRtt * 4, rtt_stats_->smoothed_rtt());
+  EXPECT_GE(kTestRtt * 4.5, rtt_stats_->smoothed_rtt());
   ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.1f);
 }
 
 // Test a simple long data transfer with 2 rtts of aggregation.
 TEST_F(BbrSenderTest, SimpleTransferAckDecimation) {
   FLAGS_quic_reloadable_flag_quic_bbr_ack_aggregation_bytes = true;
   // Decrease the CWND gain so extra CWND is required with stretch acks.
   base::SetFlag(&FLAGS_quic_bbr_cwnd_gain, 1.0);
   sender_ = new BbrSender(
       rtt_stats_,
@@ skipping 21 matching lines @@
   // bandwidth higher than the link rate.
   EXPECT_FALSE(sender_->ExportDebugState().last_sample_is_app_limited);
   // The margin here is high, because the aggregation greatly increases
   // smoothed rtt.
   EXPECT_GE(kTestRtt * 2, rtt_stats_->smoothed_rtt());
   ExpectApproxEq(kTestRtt, rtt_stats_->min_rtt(), 0.1f);
 }
 
 TEST_F(BbrSenderTest, SimpleTransferAckDecimationKeepSending) {
   FLAGS_quic_reloadable_flag_quic_bbr_ack_aggregation_bytes = false;
+  FLAGS_quic_reloadable_flag_quic_bbr_add_tso_cwnd = true;
   FLAGS_quic_reloadable_flag_quic_bbr_keep_sending_at_recent_rate = true;
   // Decrease the CWND gain so extra CWND is required with stretch acks.
   base::SetFlag(&FLAGS_quic_bbr_cwnd_gain, 1.0);
   sender_ = new BbrSender(
       rtt_stats_,
       QuicSentPacketManagerPeer::GetUnackedPacketMap(
           QuicConnectionPeer::GetSentPacketManager(bbr_sender_.connection())),
       kInitialCongestionWindowPackets, kDefaultMaxCongestionWindowPackets,
       &random_);
   QuicConnectionPeer::SetSendAlgorithm(bbr_sender_.connection(), sender_);
@@ skipping 365 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