Update from https://crrev.com/304418

net/quic/congestion_control/tcp_cubic_sender_test.cc

 // Copyright (c) 2012 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 <algorithm>
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/quic/congestion_control/rtt_stats.h"
 #include "net/quic/congestion_control/tcp_cubic_sender.h"
 #include "net/quic/congestion_control/tcp_receiver.h"
 #include "net/quic/crypto/crypto_protocol.h"
 #include "net/quic/quic_utils.h"
 #include "net/quic/test_tools/mock_clock.h"
 #include "net/quic/test_tools/quic_config_peer.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using std::make_pair;
 using std::min;
 
 namespace net {
 namespace test {
 
-const uint32 kDefaultWindowTCP = kDefaultInitialWindow * kDefaultTCPMSS;
+// TODO(ianswett): A number of theses tests were written with the assumption of
+// an initial CWND of 10. They have carefully calculated values which should be
+// updated to be based on kInitialCongestionWindowInsecure.
+const uint32 kInitialCongestionWindowPackets = 10;
+const uint32 kDefaultWindowTCP =
+    kInitialCongestionWindowPackets * kDefaultTCPMSS;
 const float kRenoBeta = 0.7f;  // Reno backoff factor.
 
-// TODO(ianswett): Remove 10000 once b/10075719 is fixed.
-const QuicPacketCount kDefaultMaxCongestionWindowTCP = 10000;
-
 class TcpCubicSenderPeer : public TcpCubicSender {
  public:
   TcpCubicSenderPeer(const QuicClock* clock,
                      bool reno,
                      QuicPacketCount max_tcp_congestion_window)
       : TcpCubicSender(
-            clock, &rtt_stats_, reno, max_tcp_congestion_window, &stats_) {
+            clock, &rtt_stats_, reno, kInitialCongestionWindowPackets,
+            max_tcp_congestion_window, &stats_) {
   }
 
   QuicPacketCount congestion_window() {
     return congestion_window_;
   }
 
   QuicPacketCount slowstart_threshold() {
     return slowstart_threshold_;
   }
 
   const HybridSlowStart& hybrid_slow_start() const {
     return hybrid_slow_start_;
   }
 
   float GetRenoBeta() const {
     return RenoBeta();
   }
 
   RttStats rtt_stats_;
   QuicConnectionStats stats_;
 };
 
 class TcpCubicSenderTest : public ::testing::Test {
  protected:
   TcpCubicSenderTest()
       : one_ms_(QuicTime::Delta::FromMilliseconds(1)),
         sender_(new TcpCubicSenderPeer(&clock_, true,
-                                       kDefaultMaxCongestionWindowTCP)),
+                                       kMaxTcpCongestionWindow)),
         receiver_(new TcpReceiver()),
         sequence_number_(1),
         acked_sequence_number_(0),
         bytes_in_flight_(0) {
     standard_packet_.bytes_sent = kDefaultTCPMSS;
   }
 
   int SendAvailableSendWindow() {
     // Send as long as TimeUntilSend returns Zero.
     int packets_sent = 0;
@@ skipping 127 matching lines @@
   const QuicByteCount cwnd = sender_->GetCongestionWindow();
   EXPECT_EQ(kDefaultWindowTCP + kDefaultTCPMSS * 2 * kNumberOfAcks, cwnd);
   EXPECT_FALSE(sender_->HasReliableBandwidthEstimate());
   EXPECT_EQ(QuicBandwidth::FromBytesAndTimeDelta(
                 cwnd, sender_->rtt_stats_.smoothed_rtt()),
             sender_->BandwidthEstimate());
 }
 
 TEST_F(TcpCubicSenderTest, SlowStartAckTrain) {
   sender_->SetNumEmulatedConnections(1);
-  EXPECT_EQ(kDefaultMaxCongestionWindowTCP * kDefaultTCPMSS,
+  EXPECT_EQ(kMaxTcpCongestionWindow * kDefaultTCPMSS,
             sender_->GetSlowStartThreshold());
 
   // Make sure that we fall out of slow start when we send ACK train longer
   // than half the RTT, in this test case 30ms, which is more than 30 calls to
   // Ack2Packets in one round.
   // Since we start at 10 packet first round will be 5 second round 10 etc
   // Hence we should pass 30 at 65 = 5 + 10 + 20 + 30
   const int kNumberOfAcks = 65;
   for (int i = 0; i < kNumberOfAcks; ++i) {
     // Send our full send window.
@@ skipping 75 matching lines @@
   EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow());
 
   // Now RTO and ensure slow start gets reset.
   EXPECT_TRUE(sender_->hybrid_slow_start().started());
   sender_->OnRetransmissionTimeout(true);
   EXPECT_FALSE(sender_->hybrid_slow_start().started());
 }
 
 TEST_F(TcpCubicSenderTest, NoPRRWhenLessThanOnePacketInFlight) {
   SendAvailableSendWindow();
-  LoseNPackets(kDefaultInitialWindow - 1);
+  LoseNPackets(kInitialCongestionWindowPackets - 1);
   AckNPackets(1);
   // PRR will allow 2 packets for every ack during recovery.
   EXPECT_EQ(2, SendAvailableSendWindow());
   // Simulate abandoning all packets by supplying a bytes_in_flight of 0.
   // PRR should now allow a packet to be sent, even though prr's state
   // variables believe it has sent enough packets.
   EXPECT_EQ(QuicTime::Delta::Zero(),
             sender_->TimeUntilSend(clock_.Now(), 0, HAS_RETRANSMITTABLE_DATA));
 }
 
@@ skipping 98 matching lines @@
 
   // Exit recovery and return to sending at the new rate.
   for (int i = 0; i < kNumberOfAcks; ++i) {
     AckNPackets(1);
     EXPECT_EQ(1, SendAvailableSendWindow());
   }
 }
 
 TEST_F(TcpCubicSenderTest, RTOCongestionWindowAndRevert) {
   EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow());
-  EXPECT_EQ(10000u, sender_->slowstart_threshold());
+  EXPECT_EQ(kMaxTcpCongestionWindow, sender_->slowstart_threshold());
 
   // Expect the window to decrease to the minimum once the RTO fires
   // and slow start threshold to be set to 1/2 of the CWND.
   sender_->OnRetransmissionTimeout(true);
   EXPECT_EQ(2 * kDefaultTCPMSS, sender_->GetCongestionWindow());
   EXPECT_EQ(5u, sender_->slowstart_threshold());
 
   // Now repair the RTO and ensure the slowstart threshold reverts.
   sender_->RevertRetransmissionTimeout();
   EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow());
-  EXPECT_EQ(10000u, sender_->slowstart_threshold());
+  EXPECT_EQ(kMaxTcpCongestionWindow, sender_->slowstart_threshold());
 }
 
 TEST_F(TcpCubicSenderTest, RTOCongestionWindowNoRetransmission) {
   EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow());
 
   // Expect the window to remain unchanged if the RTO fires but no
   // packets are retransmitted.
   sender_->OnRetransmissionTimeout(false);
   EXPECT_EQ(kDefaultWindowTCP, sender_->GetCongestionWindow());
 }
@@ skipping 118 matching lines @@
                                      sequence_number_++, kDefaultTCPMSS,
                                      NO_RETRANSMITTABLE_DATA));
 
   // Send a data packet with retransmittable data, and ensure it is tracked.
   EXPECT_TRUE(sender_->OnPacketSent(clock_.Now(), bytes_in_flight_,
                                     sequence_number_++, kDefaultTCPMSS,
                                     HAS_RETRANSMITTABLE_DATA));
 }
 
 TEST_F(TcpCubicSenderTest, ConfigureMaxInitialWindow) {
-  QuicPacketCount congestion_window = sender_->congestion_window();
   QuicConfig config;
-  QuicConfigPeer::SetReceivedInitialWindow(&config, 2 * congestion_window);
 
-  sender_->SetFromConfig(config, true);
-  EXPECT_EQ(2 * congestion_window, sender_->congestion_window());
-
-  // Verify that kCOPT: kIW10 forces the congestion window to the
-  // default of 10 regardless of ReceivedInitialWindow.
+  // Verify that kCOPT: kIW10 forces the congestion window to the default of 10.
   QuicTagVector options;
   options.push_back(kIW10);
   QuicConfigPeer::SetReceivedConnectionOptions(&config, options);
-  sender_->SetFromConfig(config, true);
-  EXPECT_EQ(congestion_window, sender_->congestion_window());
+  sender_->SetFromConfig(config,
+                         /* is_server= */ true,
+                         /* using_pacing= */ false);
+  EXPECT_EQ(10u, sender_->congestion_window());
+}
+
+TEST_F(TcpCubicSenderTest, DisableAckTrainDetectionWithPacing) {
+  EXPECT_TRUE(sender_->hybrid_slow_start().ack_train_detection());
+
+  QuicConfig config;
+  sender_->SetFromConfig(config,
+                         /* is_server= */ true,
+                         /* using_pacing= */ true);
+  EXPECT_FALSE(sender_->hybrid_slow_start().ack_train_detection());
 }
 
 TEST_F(TcpCubicSenderTest, 2ConnectionCongestionAvoidanceAtEndOfRecovery) {
   sender_->SetNumEmulatedConnections(2);
   // Ack 10 packets in 5 acks to raise the CWND to 20.
   const int kNumberOfAcks = 5;
   for (int i = 0; i < kNumberOfAcks; ++i) {
     // Send our full send window.
     SendAvailableSendWindow();
     AckNPackets(2);
@@ skipping 86 matching lines @@
 
   // Next ack should cause congestion window to grow by 1MSS.
   SendAvailableSendWindow();
   AckNPackets(2);
   expected_send_window += kDefaultTCPMSS;
   EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow());
 }
 
 }  // namespace test
 }  // namespace net