Replace QUIC's PathMtuAckListener with a non-AckListener approach. Protected by FLAGS_quic_no_mtu_d…

net/quic/quic_sent_packet_manager_test.cc

 // Copyright 2013 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/quic_sent_packet_manager.h"
 
 #include <memory>
 
 #include "base/stl_util.h"
 #include "net/quic/quic_flags.h"
@@ skipping 84 matching lines @@
     clock_.AdvanceTime(QuicTime::Delta::FromMilliseconds(1000));
     manager_.SetNetworkChangeVisitor(network_change_visitor_.get());
 
     EXPECT_CALL(*send_algorithm_, HasReliableBandwidthEstimate())
         .Times(AnyNumber());
     EXPECT_CALL(*send_algorithm_, BandwidthEstimate())
         .Times(AnyNumber())
         .WillRepeatedly(Return(QuicBandwidth::Zero()));
     EXPECT_CALL(*send_algorithm_, InSlowStart()).Times(AnyNumber());
     EXPECT_CALL(*send_algorithm_, InRecovery()).Times(AnyNumber());
+    EXPECT_CALL(*network_change_visitor_, OnPathMtuIncreased(1000))
+        .Times(AnyNumber());
   }
 
   ~QuicSentPacketManagerTest() override {
     STLDeleteElements(&packets_);
   }
 
   QuicByteCount BytesInFlight() {
     return QuicSentPacketManagerPeer::GetBytesInFlight(&manager_);
   }
   void VerifyUnackedPackets(QuicPacketNumber* packets, size_t num_packets) {
@@ skipping 1654 matching lines @@
   QuicSentPacketManagerPeer::SetConsecutiveTlpCount(&manager_, 2);
   EXPECT_EQ(2u, manager_.GetConsecutiveTlpCount());
 
   manager_.OnConnectionMigration(kDefaultPathId, PORT_CHANGE);
 
   EXPECT_EQ(2 * default_init_rtt, rtt_stats->initial_rtt_us());
   EXPECT_EQ(1u, manager_.GetConsecutiveRtoCount());
   EXPECT_EQ(2u, manager_.GetConsecutiveTlpCount());
 }
 
+TEST_P(QuicSentPacketManagerTest, PathMtuIncreased) {
+  FLAGS_quic_no_mtu_discovery_ack_listener = true;
+  EXPECT_CALL(*send_algorithm_, OnPacketSent(_, BytesInFlight(), 1, _, _))
+      .Times(1)
+      .WillOnce(Return(true));
+  SerializedPacket packet(kDefaultPathId, 1, PACKET_6BYTE_PACKET_NUMBER,
+                          nullptr, kDefaultLength + 100, 0u, false, false);
+  manager_.OnPacketSent(&packet, kInvalidPathId, 0, clock_.Now(),
+                        NOT_RETRANSMISSION, HAS_RETRANSMITTABLE_DATA);
+
+  // Ack the large packet and expect the path MTU to increase.
+  ExpectAck(1);
+  EXPECT_CALL(*network_change_visitor_,
+              OnPathMtuIncreased(kDefaultLength + 100));
+  QuicAckFrame ack_frame = InitAckFrame(1);
+  manager_.OnIncomingAck(ack_frame, clock_.Now());
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace net