When a stream is created for a QUIC session to a server which has been

net/quic/chromium/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/chromium/quic_stream_factory.h"
 
 #include <algorithm>
 #include <tuple>
 #include <utility>
 
@@ skipping 1015 matching lines @@
   }
 
   active_jobs_.erase(server_id);
   job_requests_map_.erase(requests_iter);
 }
 
 void QuicStreamFactory::OnCertVerifyJobComplete(CertVerifierJob* job, int rv) {
   active_cert_verifier_jobs_.erase(job->server_id());
 }
 
+bool QuicStreamFactory::IsQuicBroken(QuicChromiumClientSession* session) {
+  const AlternativeService alternative_service(
+      kProtoQUIC, session->server_id().host_port_pair());
+  if (!http_server_properties_->IsAlternativeServiceBroken(
+          alternative_service)) {
+    return false;
+  }
+  // No longer send requests to a server for which QUIC is broken, but
+  // continue to service existing requests.
+  OnSessionGoingAway(session);
+  return true;
+}
+
 void QuicStreamFactory::OnIdleSession(QuicChromiumClientSession* session) {}
 
 void QuicStreamFactory::OnSessionGoingAway(QuicChromiumClientSession* session) {
   const AliasSet& aliases = session_aliases_[session];
   for (AliasSet::const_iterator it = aliases.begin(); it != aliases.end();
        ++it) {
     const QuicServerId& server_id = it->server_id();
     DCHECK(active_sessions_.count(server_id));
     DCHECK_EQ(session, active_sessions_[server_id]);
     // Track sessions which have recently gone away so that we can disable
@@ skipping 654 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