Simplify RTO interaction between the QUIC sent packet manager and the

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 "net/quic/congestion_control/tcp_cubic_sender.h"
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "net/quic/congestion_control/tcp_receiver.h"
 #include "net/quic/test_tools/mock_clock.h"
@@ skipping 222 matching lines @@
   SendAvailableSendWindow();
   AckNPackets(1);
   expected_send_window += kDefaultTCPMSS;
   EXPECT_EQ(expected_send_window, sender_->SendWindow());
 }
 
 TEST_F(TcpCubicSenderTest, RTOCongestionWindow) {
   EXPECT_EQ(kDefaultWindowTCP, sender_->SendWindow());
 
   // Expect the window to decrease to the minimum once the RTO fires.
-  sender_->OnRetransmissionTimeout();
+  sender_->OnRetransmissionTimeout(true);
   EXPECT_EQ(2 * kDefaultTCPMSS, sender_->SendWindow());
 }
 
+TEST_F(TcpCubicSenderTest, RTOCongestionWindowNoRetransmission) {
+  EXPECT_EQ(kDefaultWindowTCP, sender_->SendWindow());
+
+  // Expect the window to remain unchanged if the RTO fires but no
+  // packets are retransmitted.
+  sender_->OnRetransmissionTimeout(false);
+  EXPECT_EQ(kDefaultWindowTCP, sender_->SendWindow());
+}
+
 TEST_F(TcpCubicSenderTest, RetransmissionDelay) {
   const int64 kRttMs = 10;
   const int64 kDeviationMs = 3;
   EXPECT_EQ(QuicTime::Delta::Zero(), sender_->RetransmissionDelay());
 
   sender_->AckAccounting(QuicTime::Delta::FromMilliseconds(kRttMs));
 
   // Initial value is to set the median deviation to half of the initial
   // rtt, the median in then multiplied by a factor of 4 and finally the
   // smoothed rtt is added which is the initial rtt.
@@ skipping 155 matching lines @@
   config.set_server_initial_congestion_window(2 * congestion_window,
                                        2 * congestion_window);
   EXPECT_EQ(2 * congestion_window, config.server_initial_congestion_window());
 
   sender_->SetFromConfig(config, true);
   EXPECT_EQ(2 * congestion_window, sender_->congestion_window());
 }
 
 }  // namespace test
 }  // namespace net