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

net/quic/quic_connection.h

 // 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.
 //
 // The entity that handles framing writes for a Quic client or server.
 // Each QuicSession will have a connection associated with it.
 //
 // On the server side, the Dispatcher handles the raw reads, and hands off
 // packets via ProcessUdpPacket for framing and processing.
 //
@@ skipping 444 matching lines @@
 
   // QuicPacketCreator::DelegateInterface
   void OnSerializedPacket(SerializedPacket* packet) override;
   void OnUnrecoverableError(QuicErrorCode error,
                             const std::string& error_details,
                             ConnectionCloseSource source) override;
 
   // QuicSentPacketManager::NetworkChangeVisitor
   void OnCongestionChange() override;
   void OnPathDegrading() override;
+  void OnPathMtuIncreased(QuicPacketLength packet_size) override;
 
   // Called by the crypto stream when the handshake completes. In the server's
   // case this is when the SHLO has been ACKed. Clients call this on receipt of
   // the SHLO.
   void OnHandshakeComplete();
 
   // Accessors
   void set_visitor(QuicConnectionVisitorInterface* visitor) {
     visitor_ = visitor;
   }
@@ skipping 591 matching lines @@
 
   // If true, multipath is enabled for this connection.
   bool multipath_enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicConnection);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_CONNECTION_H_