QUIC congestion option that forces ICWND to 10. Not flag protected.

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::min;
 
 namespace net {
 namespace test {
 
@@ skipping 583 matching lines @@
                                     HAS_RETRANSMITTABLE_DATA));
 }
 
 TEST_F(TcpCubicSenderTest, ConfigureMaxInitialWindow) {
   QuicTcpCongestionWindow 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.
+  QuicTagVector options;
+  options.push_back(kIW10);
+  QuicConfigPeer::SetReceivedConnectionOptions(&config, options);
+  sender_->SetFromConfig(config, true);
+  EXPECT_EQ(congestion_window, sender_->congestion_window());
 }
 
 TEST_F(TcpCubicSenderTest, CongestionAvoidanceAtEndOfRecovery) {
   // Make sure that we fall out of slow start when we encounter a packet loss.
   QuicCongestionFeedbackFrame feedback;
   // Get default QuicCongestionFeedbackFrame from receiver.
   ASSERT_TRUE(receiver_->GenerateCongestionFeedback(&feedback));
   sender_->OnIncomingQuicCongestionFeedbackFrame(feedback, clock_.Now());
   // Ack 10 packets in 5 acks to raise the CWND to 20.
   const int kNumberOfAcks = 5;
@@ skipping 32 matching lines @@
   }
 
   // Next ack should cause congestion window to grow by 1MSS.
   AckNPackets(2);
   expected_send_window += kDefaultTCPMSS;
   EXPECT_EQ(expected_send_window, sender_->GetCongestionWindow());
 }
 
 }  // namespace test
 }  // namespace net