QUIC - added force_hol_blocking field trial param to enable forced HOL blocking.

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 <openssl/aead.h>
 
 #include <algorithm>
 #include <tuple>
@@ skipping 614 matching lines @@
     int threshold_public_resets_post_handshake,
     int threshold_timeouts_with_open_streams,
     int socket_receive_buffer_size,
     bool delay_tcp_race,
     int max_server_configs_stored_in_properties,
     bool close_sessions_on_ip_change,
     bool disable_quic_on_timeout_with_open_streams,
     int idle_connection_timeout_seconds,
     bool migrate_sessions_on_network_change,
     bool migrate_sessions_early,
+    bool force_hol_blocking,
     const QuicTagVector& connection_options,
     bool enable_token_binding)
     : require_confirmation_(true),
       net_log_(net_log),
       host_resolver_(host_resolver),
       client_socket_factory_(client_socket_factory),
       http_server_properties_(http_server_properties),
       transport_security_state_(transport_security_state),
       cert_transparency_verifier_(cert_transparency_verifier),
       quic_crypto_client_stream_factory_(quic_crypto_client_stream_factory),
@@ skipping 33 matching lines @@
       delay_tcp_race_(delay_tcp_race),
       yield_after_packets_(kQuicYieldAfterPacketsRead),
       yield_after_duration_(QuicTime::Delta::FromMilliseconds(
           kQuicYieldAfterDurationMilliseconds)),
       close_sessions_on_ip_change_(close_sessions_on_ip_change),
       migrate_sessions_on_network_change_(
           migrate_sessions_on_network_change &&
           NetworkChangeNotifier::AreNetworkHandlesSupported()),
       migrate_sessions_early_(migrate_sessions_early &&
                               migrate_sessions_on_network_change_),
+      force_hol_blocking_(force_hol_blocking),
       port_seed_(random_generator_->RandUint64()),
       check_persisted_supports_quic_(true),
       has_initialized_data_(false),
       num_push_streams_created_(0),
       status_(OPEN),
       task_runner_(nullptr),
       ssl_config_service_(ssl_config_service),
       weak_factory_(this) {
   if (ssl_config_service_.get())
     ssl_config_service_->AddObserver(this);
@@ skipping 971 matching lines @@
   config.SetSocketReceiveBufferToSend(socket_receive_buffer_size_);
   config.set_max_undecryptable_packets(kMaxUndecryptablePackets);
   config.SetInitialSessionFlowControlWindowToSend(
       kQuicSessionMaxRecvWindowSize);
   config.SetInitialStreamFlowControlWindowToSend(kQuicStreamMaxRecvWindowSize);
   int64_t srtt = GetServerNetworkStatsSmoothedRttInMicroseconds(server_id);
   if (srtt > 0)
     config.SetInitialRoundTripTimeUsToSend(static_cast<uint32_t>(srtt));
   config.SetBytesForConnectionIdToSend(0);
 
+  if (force_hol_blocking_) {
+    config.SetForceHolBlocking();

[Ryan Hamilton, 2016/07/01 21:32:27]

Can we add a test to quic_stream_factory_test that the created sessions' config
has this set?

We should probably also have a test in quic_network_transaction_tests which
shows this happening. Probably a post body?

[Buck, 2016/07/08 22:17:09]

Done.

+  }

[Ryan Hamilton, 2016/07/01 21:32:27]

nit: no {}s on 1-line ifs in net/ code.

[Buck, 2016/07/08 22:17:09]

Done.

+
   if (quic_server_info_factory_.get() && !server_info) {
     // Start the disk cache loading so that we can persist the newer QUIC server
     // information and/or inform the disk cache that we have reused
     // |server_info|.
     server_info.reset(quic_server_info_factory_->GetForServer(server_id));
     server_info->Start();
   }
 
   // Use the factory to create a new socket performance watcher, and pass the
   // ownership to QuicChromiumClientSession.
@@ skipping 180 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