QUIC - Disable Preconnect when QUIC can be spoken to a server with 0RTT

net/quic/quic_stream_factory.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_stream_factory.h"
 
 #include <algorithm>
 #include <set>
 
 #include "base/location.h"
@@ skipping 667 matching lines @@
 }
 
 void QuicStreamFactory::set_require_confirmation(bool require_confirmation) {
   require_confirmation_ = require_confirmation;
   if (!(local_address_ == IPEndPoint())) {
     http_server_properties_->SetSupportsQuic(!require_confirmation,
                                              local_address_.address());
   }
 }
 
+bool QuicStreamFactory::ZeroRTTEnabledFor(const QuicServerId& quic_server_id) {
+  return !(require_confirmation_ || CryptoConfigCacheIsEmpty(quic_server_id));
+}
+
 base::TimeDelta QuicStreamFactory::GetTimeDelayForWaitingJob(
     const QuicServerId& server_id) {
   if (!delay_tcp_race_ || require_confirmation_)
     return base::TimeDelta();
   int64 srtt = 1.5 * GetServerNetworkStatsSmoothedRttInMicroseconds(server_id);
   // Picked 300ms based on mean time from
   // Net.QuicSession.HostResolution.HandshakeConfirmedTime histogram.
   const int kDefaultRTT = 300 * kNumMicrosPerMilli;
   if (!srtt)
     srtt = kDefaultRTT;
@@ skipping 755 matching lines @@
   // Since the session was active, there's no longer an
   // HttpStreamFactoryImpl::Job running which can mark it broken, unless the TCP
   // job also fails. So to avoid not using QUIC when we otherwise could, we mark
   // it as recently broken, which means that 0-RTT will be disabled but we'll
   // still race.
   http_server_properties_->MarkAlternativeServiceRecentlyBroken(
       alternative_service);
 }
 
 }  // namespace net