Adds some DVLOG statements that proved useful when debugging

net/quic/core/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/core/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1989 matching lines @@
   }
   if (debug_visitor_ != nullptr) {
     debug_visitor_->OnConnectionClosed(error, error_details, source);
   }
   // Cancel the alarms so they don't trigger any action now that the
   // connection is closed.
   CancelAllAlarms();
 }
 
 void QuicConnection::CancelAllAlarms() {
+  DVLOG(1) << "Cancelling all QuicConnection alarms.";
+
   ack_alarm_->Cancel();
   ping_alarm_->Cancel();
   resume_writes_alarm_->Cancel();
   retransmission_alarm_->Cancel();
   send_alarm_->Cancel();
   timeout_alarm_->Cancel();
   mtu_discovery_alarm_->Cancel();
 }
 
 void QuicConnection::SendGoAway(QuicErrorCode error,
@@ skipping 444 matching lines @@
 
 void QuicConnection::CheckIfApplicationLimited() {
   if (queued_packets_.empty() &&
       !sent_packet_manager_->HasPendingRetransmissions() &&
       !visitor_->WillingAndAbleToWrite()) {
     sent_packet_manager_->OnApplicationLimited();
   }
 }
 
 }  // namespace net