Adds plumbing for QUIC early connection migration. No behavior change.

net/quic/quic_connection.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/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1785 matching lines @@
   QuicTime::Delta rtt = sent_packet_manager_.GetRttStats()->smoothed_rtt();
   if (rtt.IsZero()) {
     rtt = QuicTime::Delta::FromMicroseconds(
         sent_packet_manager_.GetRttStats()->initial_rtt_us());
   }
   if (debug_visitor_)
     debug_visitor_->OnRttChanged(rtt);
   packet_generator_.OnRttChange(rtt);
 }
 
+void QuicConnection::OnPathDegrading() {
+  visitor_->OnPathDegrading();
+}
+
 void QuicConnection::OnHandshakeComplete() {
   sent_packet_manager_.SetHandshakeConfirmed();
   // The client should immediately ack the SHLO to confirm the handshake is
   // complete with the server.
   if (perspective_ == Perspective::IS_CLIENT && !ack_queued_ &&
       ack_frame_updated()) {
     ack_alarm_->Cancel();
     ack_alarm_->Set(clock_->ApproximateNow());
   }
 }
@@ skipping 720 matching lines @@
 void QuicConnection::OnPathClosed(QuicPathId path_id) {
   // Stop receiving packets on this path.
   framer_.OnPathClosed(path_id);
 }
 
 bool QuicConnection::ack_frame_updated() const {
   return received_packet_manager_.ack_frame_updated();
 }
 
 }  // namespace net