chrome/browser/io_thread.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/io_thread.h"
   6
   7 #include <vector>
   8
   9 #include "base/base64.h"
  10 #include "base/bind.h"
  11 #include "base/bind_helpers.h"
  12 #include "base/command_line.h"
  13 #include "base/compiler_specific.h"
  14 #include "base/debug/leak_tracker.h"
  15 #include "base/logging.h"
  16 #include "base/metrics/field_trial.h"
  17 #include "base/prefs/pref_registry_simple.h"
  18 #include "base/prefs/pref_service.h"
  19 #include "base/profiler/scoped_tracker.h"
  20 #include "base/stl_util.h"
  21 #include "base/strings/string_number_conversions.h"
  22 #include "base/strings/string_piece.h"
  23 #include "base/strings/string_split.h"
  24 #include "base/strings/string_util.h"
  25 #include "base/threading/sequenced_worker_pool.h"
  26 #include "base/threading/thread.h"
  27 #include "base/threading/worker_pool.h"
  28 #include "base/time/time.h"
  29 #include "base/trace_event/trace_event.h"
  30 #include "build/build_config.h"
  31 #include "chrome/browser/browser_process.h"
  32 #include "chrome/browser/net/async_dns_field_trial.h"
  33 #include "chrome/browser/net/chrome_net_log.h"
  34 #include "chrome/browser/net/chrome_network_delegate.h"
  35 #include "chrome/browser/net/connect_interceptor.h"
  36 #include "chrome/browser/net/dns_probe_service.h"
  37 #include "chrome/browser/net/pref_proxy_config_tracker.h"
  38 #include "chrome/browser/net/proxy_service_factory.h"
  39 #include "chrome/common/chrome_content_client.h"
  40 #include "chrome/common/chrome_switches.h"
  41 #include "chrome/common/chrome_version_info.h"
  42 #include "chrome/common/pref_names.h"
  43 #include "components/data_reduction_proxy/core/browser/data_reduction_proxy_prefs.h"
  44 #include "components/data_reduction_proxy/core/common/data_reduction_proxy_params.h"
  45 #include "components/policy/core/common/policy_service.h"
  46 #include "components/variations/variations_associated_data.h"
  47 #include "content/public/browser/browser_thread.h"
  48 #include "content/public/browser/cookie_store_factory.h"
  49 #include "net/base/host_mapping_rules.h"
  50 #include "net/base/net_util.h"
  51 #include "net/base/network_quality_estimator.h"
  52 #include "net/base/sdch_manager.h"
  53 #include "net/cert/cert_policy_enforcer.h"
  54 #include "net/cert/cert_verifier.h"
  55 #include "net/cert/cert_verify_proc.h"
  56 #include "net/cert/ct_known_logs.h"
  57 #include "net/cert/ct_known_logs_static.h"
  58 #include "net/cert/ct_log_verifier.h"
  59 #include "net/cert/ct_verifier.h"
  60 #include "net/cert/multi_log_ct_verifier.h"
  61 #include "net/cert/multi_threaded_cert_verifier.h"
  62 #include "net/cookies/cookie_store.h"
  63 #include "net/dns/host_cache.h"
  64 #include "net/dns/host_resolver.h"
  65 #include "net/dns/mapped_host_resolver.h"
  66 #include "net/ftp/ftp_network_layer.h"
  67 #include "net/http/http_auth_filter.h"
  68 #include "net/http/http_auth_handler_factory.h"
  69 #include "net/http/http_network_layer.h"
  70 #include "net/http/http_server_properties_impl.h"
  71 #include "net/proxy/proxy_config_service.h"
  72 #include "net/proxy/proxy_script_fetcher_impl.h"
  73 #include "net/proxy/proxy_service.h"
  74 #include "net/quic/crypto/crypto_protocol.h"
  75 #include "net/quic/quic_protocol.h"
  76 #include "net/quic/quic_utils.h"
  77 #include "net/socket/tcp_client_socket.h"
  78 #include "net/spdy/spdy_session.h"
  79 #include "net/ssl/channel_id_service.h"
  80 #include "net/ssl/default_channel_id_store.h"
  81 #include "net/url_request/data_protocol_handler.h"
  82 #include "net/url_request/file_protocol_handler.h"
  83 #include "net/url_request/ftp_protocol_handler.h"
  84 #include "net/url_request/static_http_user_agent_settings.h"
  85 #include "net/url_request/url_fetcher.h"
  86 #include "net/url_request/url_request_context.h"
  87 #include "net/url_request/url_request_context_getter.h"
  88 #include "net/url_request/url_request_job_factory_impl.h"
  89 #include "net/url_request/url_request_throttler_manager.h"
  90 #include "url/url_constants.h"
  91
  92 #if defined(ENABLE_CONFIGURATION_POLICY)
  93 #include "policy/policy_constants.h"
  94 #endif
  95
  96 #if defined(ENABLE_EXTENSIONS)
  97 #include "chrome/browser/extensions/event_router_forwarder.h"
  98 #endif
  99
 100 #if defined(USE_NSS_CERTS) || defined(OS_IOS)
 101 #include "net/cert_net/nss_ocsp.h"
 102 #endif
 103
 104 #if defined(OS_ANDROID)
 105 #include "base/android/build_info.h"
 106 #endif
 107
 108 #if defined(OS_CHROMEOS)
 109 #include "chrome/browser/chromeos/net/cert_verify_proc_chromeos.h"
 110 #include "chromeos/network/host_resolver_impl_chromeos.h"
 111 #endif
 112
 113 using content::BrowserThread;
 114
 115 class SafeBrowsingURLRequestContext;
 116
 117 // The IOThread object must outlive any tasks posted to the IO thread before the
 118 // Quit task, so base::Bind() calls are not refcounted.
 119
 120 namespace {
 121
 122 const char kTCPFastOpenFieldTrialName[] = "TCPFastOpen";
 123 const char kTCPFastOpenHttpsEnabledGroupName[] = "HttpsEnabled";
 124
 125 const char kQuicFieldTrialName[] = "QUIC";
 126 const char kQuicFieldTrialEnabledGroupName[] = "Enabled";
 127 const char kQuicFieldTrialHttpsEnabledGroupName[] = "HttpsEnabled";
 128
 129 // The SPDY trial composes two different trial plus control groups:
 130 //  * A "holdback" group with SPDY disabled, and corresponding control
 131 //  (SPDY/3.1). The primary purpose of the holdback group is to encourage site
 132 //  operators to do feature detection rather than UA-sniffing. As such, this
 133 //  trial runs continuously.
 134 //  * A SPDY/4 experiment, for SPDY/4 (aka HTTP/2) vs SPDY/3.1 comparisons and
 135 //  eventual SPDY/4 deployment.
 136 const char kSpdyFieldTrialName[] = "SPDY";
 137 const char kSpdyFieldTrialHoldbackGroupNamePrefix[] = "SpdyDisabled";
 138 const char kSpdyFieldTrialSpdy31GroupNamePrefix[] = "Spdy31Enabled";
 139 const char kSpdyFieldTrialSpdy4GroupNamePrefix[] = "Spdy4Enabled";
 140 const char kSpdyFieldTrialParametrizedPrefix[] = "Parametrized";
 141
 142 #if defined(OS_MACOSX) && !defined(OS_IOS)
 143 void ObserveKeychainEvents() {
 144   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 145   net::CertDatabase::GetInstance()->SetMessageLoopForKeychainEvents();
 146 }
 147 #endif
 148
 149 // Used for the "system" URLRequestContext.
 150 class SystemURLRequestContext : public net::URLRequestContext {
 151  public:
 152   SystemURLRequestContext() {
 153 #if defined(USE_NSS_CERTS) || defined(OS_IOS)
 154     net::SetURLRequestContextForNSSHttpIO(this);
 155 #endif
 156   }
 157
 158  private:
 159   ~SystemURLRequestContext() override {
 160     AssertNoURLRequests();
 161 #if defined(USE_NSS_CERTS) || defined(OS_IOS)
 162     net::SetURLRequestContextForNSSHttpIO(NULL);
 163 #endif
 164   }
 165 };
 166
 167 scoped_ptr<net::HostResolver> CreateGlobalHostResolver(net::NetLog* net_log) {
 168   TRACE_EVENT0("startup", "IOThread::CreateGlobalHostResolver");
 169   const base::CommandLine& command_line =
 170       *base::CommandLine::ForCurrentProcess();
 171
 172   net::HostResolver::Options options;
 173
 174   // Use the retry attempts override from the command-line, if any.
 175   if (command_line.HasSwitch(switches::kHostResolverRetryAttempts)) {
 176     std::string s =
 177         command_line.GetSwitchValueASCII(switches::kHostResolverRetryAttempts);
 178     // Parse the switch (it should be a non-negative integer).
 179     int n;
 180     if (base::StringToInt(s, &n) && n >= 0) {
 181       options.max_retry_attempts = static_cast<size_t>(n);
 182     } else {
 183       LOG(ERROR) << "Invalid switch for host resolver retry attempts: " << s;
 184     }
 185   }
 186
 187   scoped_ptr<net::HostResolver> global_host_resolver;
 188 #if defined OS_CHROMEOS
 189   global_host_resolver =
 190       chromeos::HostResolverImplChromeOS::CreateSystemResolver(options,
 191                                                                net_log);
 192 #else
 193   global_host_resolver =
 194       net::HostResolver::CreateSystemResolver(options, net_log);
 195 #endif
 196
 197   // If hostname remappings were specified on the command-line, layer these
 198   // rules on top of the real host resolver. This allows forwarding all requests
 199   // through a designated test server.
 200   if (!command_line.HasSwitch(switches::kHostResolverRules))
 201     return global_host_resolver.Pass();
 202
 203   scoped_ptr<net::MappedHostResolver> remapped_resolver(
 204       new net::MappedHostResolver(global_host_resolver.Pass()));
 205   remapped_resolver->SetRulesFromString(
 206       command_line.GetSwitchValueASCII(switches::kHostResolverRules));
 207   return remapped_resolver.Pass();
 208 }
 209
 210 // TODO(willchan): Remove proxy script fetcher context since it's not necessary
 211 // now that I got rid of refcounting URLRequestContexts.
 212 // See IOThread::Globals for details.
 213 net::URLRequestContext*
 214 ConstructProxyScriptFetcherContext(IOThread::Globals* globals,
 215                                    net::NetLog* net_log) {
 216   net::URLRequestContext* context = new net::URLRequestContext;
 217   context->set_net_log(net_log);
 218   context->set_host_resolver(globals->host_resolver.get());
 219   context->set_cert_verifier(globals->cert_verifier.get());
 220   context->set_transport_security_state(
 221       globals->transport_security_state.get());
 222   context->set_cert_transparency_verifier(
 223       globals->cert_transparency_verifier.get());
 224   context->set_http_auth_handler_factory(
 225       globals->http_auth_handler_factory.get());
 226   context->set_proxy_service(globals->proxy_script_fetcher_proxy_service.get());
 227   context->set_http_transaction_factory(
 228       globals->proxy_script_fetcher_http_transaction_factory.get());
 229   context->set_job_factory(
 230       globals->proxy_script_fetcher_url_request_job_factory.get());
 231   context->set_cookie_store(globals->system_cookie_store.get());
 232   context->set_channel_id_service(
 233       globals->system_channel_id_service.get());
 234   context->set_network_delegate(globals->system_network_delegate.get());
 235   context->set_http_user_agent_settings(
 236       globals->http_user_agent_settings.get());
 237   // TODO(rtenneti): We should probably use HttpServerPropertiesManager for the
 238   // system URLRequestContext too. There's no reason this should be tied to a
 239   // profile.
 240   return context;
 241 }
 242
 243 net::URLRequestContext*
 244 ConstructSystemRequestContext(IOThread::Globals* globals,
 245                               net::NetLog* net_log) {
 246   net::URLRequestContext* context = new SystemURLRequestContext;
 247   context->set_net_log(net_log);
 248   context->set_host_resolver(globals->host_resolver.get());
 249   context->set_cert_verifier(globals->cert_verifier.get());
 250   context->set_transport_security_state(
 251       globals->transport_security_state.get());
 252   context->set_cert_transparency_verifier(
 253       globals->cert_transparency_verifier.get());
 254   context->set_http_auth_handler_factory(
 255       globals->http_auth_handler_factory.get());
 256   context->set_proxy_service(globals->system_proxy_service.get());
 257   context->set_http_transaction_factory(
 258       globals->system_http_transaction_factory.get());
 259   context->set_job_factory(globals->system_url_request_job_factory.get());
 260   context->set_cookie_store(globals->system_cookie_store.get());
 261   context->set_channel_id_service(
 262       globals->system_channel_id_service.get());
 263   context->set_throttler_manager(globals->throttler_manager.get());
 264   context->set_network_delegate(globals->system_network_delegate.get());
 265   context->set_http_user_agent_settings(
 266       globals->http_user_agent_settings.get());
 267   context->set_network_quality_estimator(
 268       globals->network_quality_estimator.get());
 269   return context;
 270 }
 271
 272 int GetSwitchValueAsInt(const base::CommandLine& command_line,
 273                         const std::string& switch_name) {
 274   int value;
 275   if (!base::StringToInt(command_line.GetSwitchValueASCII(switch_name),
 276                          &value)) {
 277     return 0;
 278   }
 279   return value;
 280 }
 281
 282 // Returns the value associated with |key| in |params| or "" if the
 283 // key is not present in the map.
 284 const std::string& GetVariationParam(
 285     const std::map<std::string, std::string>& params,
 286     const std::string& key) {
 287   std::map<std::string, std::string>::const_iterator it = params.find(key);
 288   if (it == params.end())
 289     return base::EmptyString();
 290
 291   return it->second;
 292 }
 293
 294 // Parse kUseSpdy command line flag options, which may contain the following:
 295 //
 296 //   "off"                      : Disables SPDY support entirely.
 297 //   "no-ping"                  : Disables SPDY ping connection testing.
 298 //   "exclude=<host>"           : Disables SPDY support for the host <host>.
 299 //   "no-compress"              : Disables SPDY header compression.
 300 //   "no-alt-protocols          : Disables alternate protocol support.
 301 //   "init-max-streams=<limit>" : Specifies the maximum number of concurrent
 302 //                                streams for a SPDY session, unless the
 303 //                                specifies a different value via SETTINGS.
 304 void ConfigureSpdyGlobalsFromUseSpdyArgument(const std::string& mode,
 305                                              IOThread::Globals* globals) {
 306   static const char kOff[] = "off";
 307   static const char kDisablePing[] = "no-ping";
 308   static const char kExclude[] = "exclude";  // Hosts to exclude
 309   static const char kDisableCompression[] = "no-compress";
 310   static const char kDisableAltProtocols[] = "no-alt-protocols";
 311   static const char kInitialMaxConcurrentStreams[] = "init-max-streams";
 312
 313   std::vector<std::string> spdy_options;
 314   base::SplitString(mode, ',', &spdy_options);
 315
 316   for (const std::string& element : spdy_options) {
 317     std::vector<std::string> name_value;
 318     base::SplitString(element, '=', &name_value);
 319     const std::string& option =
 320         name_value.size() > 0 ? name_value[0] : std::string();
 321     const std::string value =
 322         name_value.size() > 1 ? name_value[1] : std::string();
 323
 324     if (option == kOff) {
 325       net::HttpStreamFactory::set_spdy_enabled(false);
 326       continue;
 327     }
 328     if (option == kDisablePing) {
 329       globals->enable_spdy_ping_based_connection_checking.set(false);
 330       continue;
 331     }
 332     if (option == kExclude) {
 333       globals->forced_spdy_exclusions.insert(
 334           net::HostPortPair::FromURL(GURL(value)));
 335       continue;
 336     }
 337     if (option == kDisableCompression) {
 338       globals->enable_spdy_compression.set(false);
 339       continue;
 340     }
 341     if (option == kDisableAltProtocols) {
 342       globals->use_alternate_protocols.set(false);
 343       continue;
 344     }
 345     if (option == kInitialMaxConcurrentStreams) {
 346       int streams;
 347       if (base::StringToInt(value, &streams)) {
 348         globals->initial_max_spdy_concurrent_streams.set(streams);
 349         continue;
 350       }
 351     }
 352     LOG(DFATAL) << "Unrecognized spdy option: " << option;
 353   }
 354 }
 355
 356 }  // namespace
 357
 358 class IOThread::LoggingNetworkChangeObserver
 359     : public net::NetworkChangeNotifier::IPAddressObserver,
 360       public net::NetworkChangeNotifier::ConnectionTypeObserver,
 361       public net::NetworkChangeNotifier::NetworkChangeObserver {
 362  public:
 363   // |net_log| must remain valid throughout our lifetime.
 364   explicit LoggingNetworkChangeObserver(net::NetLog* net_log)
 365       : net_log_(net_log) {
 366     net::NetworkChangeNotifier::AddIPAddressObserver(this);
 367     net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
 368     net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
 369   }
 370
 371   ~LoggingNetworkChangeObserver() override {
 372     net::NetworkChangeNotifier::RemoveIPAddressObserver(this);
 373     net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
 374     net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
 375   }
 376
 377   // NetworkChangeNotifier::IPAddressObserver implementation.
 378   void OnIPAddressChanged() override {
 379     VLOG(1) << "Observed a change to the network IP addresses";
 380
 381     net_log_->AddGlobalEntry(net::NetLog::TYPE_NETWORK_IP_ADDRESSES_CHANGED);
 382   }
 383
 384   // NetworkChangeNotifier::ConnectionTypeObserver implementation.
 385   void OnConnectionTypeChanged(
 386       net::NetworkChangeNotifier::ConnectionType type) override {
 387     std::string type_as_string =
 388         net::NetworkChangeNotifier::ConnectionTypeToString(type);
 389
 390     VLOG(1) << "Observed a change to network connectivity state "
 391             << type_as_string;
 392
 393     net_log_->AddGlobalEntry(
 394         net::NetLog::TYPE_NETWORK_CONNECTIVITY_CHANGED,
 395         net::NetLog::StringCallback("new_connection_type", &type_as_string));
 396   }
 397
 398   // NetworkChangeNotifier::NetworkChangeObserver implementation.
 399   void OnNetworkChanged(
 400       net::NetworkChangeNotifier::ConnectionType type) override {
 401     std::string type_as_string =
 402         net::NetworkChangeNotifier::ConnectionTypeToString(type);
 403
 404     VLOG(1) << "Observed a network change to state " << type_as_string;
 405
 406     net_log_->AddGlobalEntry(
 407         net::NetLog::TYPE_NETWORK_CHANGED,
 408         net::NetLog::StringCallback("new_connection_type", &type_as_string));
 409   }
 410
 411  private:
 412   net::NetLog* net_log_;
 413   DISALLOW_COPY_AND_ASSIGN(LoggingNetworkChangeObserver);
 414 };
 415
 416 class SystemURLRequestContextGetter : public net::URLRequestContextGetter {
 417  public:
 418   explicit SystemURLRequestContextGetter(IOThread* io_thread);
 419
 420   // Implementation for net::UrlRequestContextGetter.
 421   net::URLRequestContext* GetURLRequestContext() override;
 422   scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner()
 423       const override;
 424
 425  protected:
 426   ~SystemURLRequestContextGetter() override;
 427
 428  private:
 429   IOThread* const io_thread_;  // Weak pointer, owned by BrowserProcess.
 430   scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
 431
 432   base::debug::LeakTracker<SystemURLRequestContextGetter> leak_tracker_;
 433 };
 434
 435 SystemURLRequestContextGetter::SystemURLRequestContextGetter(
 436     IOThread* io_thread)
 437     : io_thread_(io_thread),
 438       network_task_runner_(
 439           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO)) {
 440 }
 441
 442 SystemURLRequestContextGetter::~SystemURLRequestContextGetter() {}
 443
 444 net::URLRequestContext* SystemURLRequestContextGetter::GetURLRequestContext() {
 445   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 446   DCHECK(io_thread_->globals()->system_request_context.get());
 447
 448   return io_thread_->globals()->system_request_context.get();
 449 }
 450
 451 scoped_refptr<base::SingleThreadTaskRunner>
 452 SystemURLRequestContextGetter::GetNetworkTaskRunner() const {
 453   return network_task_runner_;
 454 }
 455
 456 IOThread::Globals::
 457 SystemRequestContextLeakChecker::SystemRequestContextLeakChecker(
 458     Globals* globals)
 459     : globals_(globals) {
 460   DCHECK(globals_);
 461 }
 462
 463 IOThread::Globals::
 464 SystemRequestContextLeakChecker::~SystemRequestContextLeakChecker() {
 465   if (globals_->system_request_context.get())
 466     globals_->system_request_context->AssertNoURLRequests();
 467 }
 468
 469 IOThread::Globals::Globals()
 470     : system_request_context_leak_checker(this),
 471       ignore_certificate_errors(false),
 472       testing_fixed_http_port(0),
 473       testing_fixed_https_port(0),
 474       enable_user_alternate_protocol_ports(false) {
 475 }
 476
 477 IOThread::Globals::~Globals() {}
 478
 479 // |local_state| is passed in explicitly in order to (1) reduce implicit
 480 // dependencies and (2) make IOThread more flexible for testing.
 481 IOThread::IOThread(
 482     PrefService* local_state,
 483     policy::PolicyService* policy_service,
 484     ChromeNetLog* net_log,
 485     extensions::EventRouterForwarder* extension_event_router_forwarder)
 486     : net_log_(net_log),
 487 #if defined(ENABLE_EXTENSIONS)
 488       extension_event_router_forwarder_(extension_event_router_forwarder),
 489 #endif
 490       globals_(NULL),
 491       is_spdy_disabled_by_policy_(false),
 492       is_quic_allowed_by_policy_(true),
 493       creation_time_(base::TimeTicks::Now()),
 494       weak_factory_(this) {
 495   auth_schemes_ = local_state->GetString(prefs::kAuthSchemes);
 496   negotiate_disable_cname_lookup_ = local_state->GetBoolean(
 497       prefs::kDisableAuthNegotiateCnameLookup);
 498   negotiate_enable_port_ = local_state->GetBoolean(
 499       prefs::kEnableAuthNegotiatePort);
 500   auth_server_whitelist_ = local_state->GetString(prefs::kAuthServerWhitelist);
 501   auth_delegate_whitelist_ = local_state->GetString(
 502       prefs::kAuthNegotiateDelegateWhitelist);
 503   gssapi_library_name_ = local_state->GetString(prefs::kGSSAPILibraryName);
 504   pref_proxy_config_tracker_.reset(
 505       ProxyServiceFactory::CreatePrefProxyConfigTrackerOfLocalState(
 506           local_state));
 507   ChromeNetworkDelegate::InitializePrefsOnUIThread(
 508       &system_enable_referrers_,
 509       NULL,
 510       NULL,
 511       NULL,
 512       local_state);
 513   ssl_config_service_manager_.reset(
 514       SSLConfigServiceManager::CreateDefaultManager(local_state));
 515
 516   base::Value* dns_client_enabled_default = new base::FundamentalValue(
 517       chrome_browser_net::ConfigureAsyncDnsFieldTrial());
 518   local_state->SetDefaultPrefValue(prefs::kBuiltInDnsClientEnabled,
 519                                    dns_client_enabled_default);
 520   chrome_browser_net::LogAsyncDnsPrefSource(
 521       local_state->FindPreference(prefs::kBuiltInDnsClientEnabled));
 522
 523   dns_client_enabled_.Init(prefs::kBuiltInDnsClientEnabled,
 524                            local_state,
 525                            base::Bind(&IOThread::UpdateDnsClientEnabled,
 526                                       base::Unretained(this)));
 527   dns_client_enabled_.MoveToThread(
 528       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 529
 530   quick_check_enabled_.Init(prefs::kQuickCheckEnabled,
 531                             local_state);
 532   quick_check_enabled_.MoveToThread(
 533       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
 534
 535 #if defined(ENABLE_CONFIGURATION_POLICY)
 536   is_spdy_disabled_by_policy_ = policy_service->GetPolicies(
 537       policy::PolicyNamespace(policy::POLICY_DOMAIN_CHROME, std::string())).Get(
 538           policy::key::kDisableSpdy) != NULL;
 539
 540   const base::Value* value = policy_service->GetPolicies(
 541       policy::PolicyNamespace(policy::POLICY_DOMAIN_CHROME,
 542       std::string())).GetValue(policy::key::kQuicAllowed);
 543   if (value)
 544     value->GetAsBoolean(&is_quic_allowed_by_policy_);
 545 #endif  // ENABLE_CONFIGURATION_POLICY
 546
 547   BrowserThread::SetDelegate(BrowserThread::IO, this);
 548 }
 549
 550 IOThread::~IOThread() {
 551   // This isn't needed for production code, but in tests, IOThread may
 552   // be multiply constructed.
 553   BrowserThread::SetDelegate(BrowserThread::IO, NULL);
 554
 555   pref_proxy_config_tracker_->DetachFromPrefService();
 556   DCHECK(!globals_);
 557 }
 558
 559 IOThread::Globals* IOThread::globals() {
 560   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 561   return globals_;
 562 }
 563
 564 void IOThread::SetGlobalsForTesting(Globals* globals) {
 565   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 566   DCHECK(!globals || !globals_);
 567   globals_ = globals;
 568 }
 569
 570 ChromeNetLog* IOThread::net_log() {
 571   return net_log_;
 572 }
 573
 574 void IOThread::ChangedToOnTheRecord() {
 575   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 576   BrowserThread::PostTask(
 577       BrowserThread::IO,
 578       FROM_HERE,
 579       base::Bind(&IOThread::ChangedToOnTheRecordOnIOThread,
 580                  base::Unretained(this)));
 581 }
 582
 583 net::URLRequestContextGetter* IOThread::system_url_request_context_getter() {
 584   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 585   if (!system_url_request_context_getter_.get()) {
 586     InitSystemRequestContext();
 587   }
 588   return system_url_request_context_getter_.get();
 589 }
 590
 591 void IOThread::Init() {
 592   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 593   // is fixed.
 594   tracked_objects::ScopedTracker tracking_profile1(
 595       FROM_HERE_WITH_EXPLICIT_FUNCTION("466432 IOThread::InitAsync::Start"));
 596   TRACE_EVENT0("startup", "IOThread::InitAsync");
 597   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 598
 599 #if defined(USE_NSS_CERTS) || defined(OS_IOS)
 600   net::SetMessageLoopForNSSHttpIO();
 601 #endif
 602
 603   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 604   // is fixed.
 605   tracked_objects::ScopedTracker tracking_profile2(
 606       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 607           "466432 IOThread::InitAsync::CommandLineForCurrentProcess"));
 608   const base::CommandLine& command_line =
 609       *base::CommandLine::ForCurrentProcess();
 610
 611   DCHECK(!globals_);
 612   globals_ = new Globals;
 613
 614   // Add an observer that will emit network change events to the ChromeNetLog.
 615   // Assuming NetworkChangeNotifier dispatches in FIFO order, we should be
 616   // logging the network change before other IO thread consumers respond to it.
 617   network_change_observer_.reset(
 618       new LoggingNetworkChangeObserver(net_log_));
 619
 620   // Setup the HistogramWatcher to run on the IO thread.
 621   net::NetworkChangeNotifier::InitHistogramWatcher();
 622
 623 #if defined(ENABLE_EXTENSIONS)
 624   globals_->extension_event_router_forwarder =
 625       extension_event_router_forwarder_;
 626 #endif
 627
 628   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 629   // is fixed.
 630   tracked_objects::ScopedTracker tracking_profile3(
 631       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 632           "466432 IOThread::InitAsync::ChromeNetworkDelegate"));
 633   scoped_ptr<ChromeNetworkDelegate> chrome_network_delegate(
 634       new ChromeNetworkDelegate(extension_event_router_forwarder(),
 635                                 &system_enable_referrers_));
 636
 637   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 638   // is fixed.
 639   tracked_objects::ScopedTracker tracking_profile4(
 640       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 641           "466432 IOThread::InitAsync::CreateGlobalHostResolver"));
 642   globals_->system_network_delegate = chrome_network_delegate.Pass();
 643   globals_->host_resolver = CreateGlobalHostResolver(net_log_);
 644
 645   globals_->network_quality_estimator.reset(new net::NetworkQualityEstimator());
 646
 647   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 648   // is fixed.
 649   tracked_objects::ScopedTracker tracking_profile5(
 650       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 651           "466432 IOThread::InitAsync::UpdateDnsClientEnabled::Start"));
 652   UpdateDnsClientEnabled();
 653   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 654   // is fixed.
 655   tracked_objects::ScopedTracker tracking_profile6(
 656       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 657           "466432 IOThread::InitAsync::UpdateDnsClientEnabled::End"));
 658 #if defined(OS_CHROMEOS)
 659   // Creates a CertVerifyProc that doesn't allow any profile-provided certs.
 660   globals_->cert_verifier.reset(new net::MultiThreadedCertVerifier(
 661       new chromeos::CertVerifyProcChromeOS()));
 662 #else
 663   globals_->cert_verifier.reset(new net::MultiThreadedCertVerifier(
 664       net::CertVerifyProc::CreateDefault()));
 665 #endif
 666
 667   globals_->transport_security_state.reset(new net::TransportSecurityState());
 668
 669   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 670   // is fixed.
 671   tracked_objects::ScopedTracker tracking_profile7(
 672       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 673           "466432 IOThread::InitAsync::CreateMultiLogVerifier"));
 674   net::MultiLogCTVerifier* ct_verifier = new net::MultiLogCTVerifier();
 675   globals_->cert_transparency_verifier.reset(ct_verifier);
 676
 677   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 678   // is fixed.
 679   tracked_objects::ScopedTracker tracking_profile8(
 680       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 681           "466432 IOThread::InitAsync::CreateLogVerifiers::Start"));
 682   // Add built-in logs
 683   ct_verifier->AddLogs(net::ct::CreateLogVerifiersForKnownLogs());
 684   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 685   // is fixed.
 686   tracked_objects::ScopedTracker tracking_profile9(
 687       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 688           "466432 IOThread::InitAsync::CreateLogVerifiers::End"));
 689
 690   // Add logs from command line
 691   if (command_line.HasSwitch(switches::kCertificateTransparencyLog)) {
 692     std::string switch_value = command_line.GetSwitchValueASCII(
 693         switches::kCertificateTransparencyLog);
 694     std::vector<std::string> logs;
 695     base::SplitString(switch_value, ',', &logs);
 696     for (std::vector<std::string>::iterator it = logs.begin(); it != logs.end();
 697          ++it) {
 698       const std::string& curr_log = *it;
 699       std::vector<std::string> log_metadata;
 700       base::SplitString(curr_log, ':', &log_metadata);
 701       CHECK_GE(log_metadata.size(), 3u)
 702           << "CT log metadata missing: Switch format is "
 703           << "'description:base64_key:url_without_schema'.";
 704       std::string log_description(log_metadata[0]);
 705       std::string log_url(std::string("https://") + log_metadata[2]);
 706       std::string ct_public_key_data;
 707       CHECK(base::Base64Decode(log_metadata[1], &ct_public_key_data))
 708           << "Unable to decode CT public key.";
 709       scoped_ptr<net::CTLogVerifier> external_log_verifier(
 710           net::CTLogVerifier::Create(ct_public_key_data, log_description,
 711                                      log_url));
 712       CHECK(external_log_verifier) << "Unable to parse CT public key.";
 713       VLOG(1) << "Adding log with description " << log_description;
 714       ct_verifier->AddLog(external_log_verifier.Pass());
 715     }
 716   }
 717
 718   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 719   // is fixed.
 720   tracked_objects::ScopedTracker tracking_profile10(
 721       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 722           "466432 IOThread::InitAsync::CertPolicyEnforcer"));
 723   net::CertPolicyEnforcer* policy_enforcer = new net::CertPolicyEnforcer;
 724   globals_->cert_policy_enforcer.reset(policy_enforcer);
 725
 726   globals_->ssl_config_service = GetSSLConfigService();
 727
 728   globals_->http_auth_handler_factory.reset(CreateDefaultAuthHandlerFactory(
 729       globals_->host_resolver.get()));
 730   globals_->http_server_properties.reset(new net::HttpServerPropertiesImpl());
 731   // For the ProxyScriptFetcher, we use a direct ProxyService.
 732   globals_->proxy_script_fetcher_proxy_service.reset(
 733       net::ProxyService::CreateDirectWithNetLog(net_log_));
 734   // In-memory cookie store.
 735   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 736   // is fixed.
 737   tracked_objects::ScopedTracker tracking_profile11(
 738       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 739           "466432 IOThread::InitAsync::CreateCookieStore::Start"));
 740   globals_->system_cookie_store =
 741         content::CreateCookieStore(content::CookieStoreConfig());
 742   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 743   // is fixed.
 744   tracked_objects::ScopedTracker tracking_profile12(
 745       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 746           "466432 IOThread::InitAsync::CreateCookieStore::End"));
 747   // In-memory channel ID store.
 748   globals_->system_channel_id_service.reset(
 749       new net::ChannelIDService(
 750           new net::DefaultChannelIDStore(NULL),
 751           base::WorkerPool::GetTaskRunner(true)));
 752   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 753   // is fixed.
 754   tracked_objects::ScopedTracker tracking_profile12_1(
 755       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 756           "466432 IOThread::InitAsync::CreateDnsProbeService"));
 757   globals_->dns_probe_service.reset(new chrome_browser_net::DnsProbeService());
 758   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 759   // is fixed.
 760   tracked_objects::ScopedTracker tracking_profile12_2(
 761       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 762           "466432 IOThread::InitAsync::CreateHostMappingRules"));
 763   globals_->host_mapping_rules.reset(new net::HostMappingRules());
 764   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 765   // is fixed.
 766   tracked_objects::ScopedTracker tracking_profile12_3(
 767       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 768           "466432 IOThread::InitAsync::CreateHTTPUserAgentSettings"));
 769   globals_->http_user_agent_settings.reset(
 770       new net::StaticHttpUserAgentSettings(std::string(), GetUserAgent()));
 771   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 772   // is fixed.
 773   tracked_objects::ScopedTracker tracking_profile12_4(
 774       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 775           "466432 IOThread::InitAsync::CommandLineConfiguration"));
 776   if (command_line.HasSwitch(switches::kHostRules)) {
 777     TRACE_EVENT_BEGIN0("startup", "IOThread::InitAsync:SetRulesFromString");
 778     globals_->host_mapping_rules->SetRulesFromString(
 779         command_line.GetSwitchValueASCII(switches::kHostRules));
 780     TRACE_EVENT_END0("startup", "IOThread::InitAsync:SetRulesFromString");
 781   }
 782   if (command_line.HasSwitch(switches::kIgnoreCertificateErrors))
 783     globals_->ignore_certificate_errors = true;
 784   if (command_line.HasSwitch(switches::kTestingFixedHttpPort)) {
 785     globals_->testing_fixed_http_port =
 786         GetSwitchValueAsInt(command_line, switches::kTestingFixedHttpPort);
 787   }
 788   if (command_line.HasSwitch(switches::kTestingFixedHttpsPort)) {
 789     globals_->testing_fixed_https_port =
 790         GetSwitchValueAsInt(command_line, switches::kTestingFixedHttpsPort);
 791   }
 792   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 793   // is fixed.
 794   tracked_objects::ScopedTracker tracking_profile12_5(
 795       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 796           "466432 IOThread::InitAsync::QuicConfiguration"));
 797   ConfigureQuic(command_line);
 798   if (command_line.HasSwitch(
 799           switches::kEnableUserAlternateProtocolPorts)) {
 800     globals_->enable_user_alternate_protocol_ports = true;
 801   }
 802   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 803   // is fixed.
 804   tracked_objects::ScopedTracker tracking_profile13(
 805       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 806           "466432 IOThread::InitAsync::InitializeNetworkOptions"));
 807   InitializeNetworkOptions(command_line);
 808
 809   net::HttpNetworkSession::Params session_params;
 810   InitializeNetworkSessionParams(&session_params);
 811   session_params.net_log = net_log_;
 812   session_params.proxy_service =
 813       globals_->proxy_script_fetcher_proxy_service.get();
 814
 815   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 816   // is fixed.
 817   tracked_objects::ScopedTracker tracking_profile14(
 818       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 819           "466432 IOThread::InitAsync::HttpNetorkSession::Start"));
 820   TRACE_EVENT_BEGIN0("startup", "IOThread::InitAsync:HttpNetworkSession");
 821   scoped_refptr<net::HttpNetworkSession> network_session(
 822       new net::HttpNetworkSession(session_params));
 823   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 824   // is fixed.
 825   tracked_objects::ScopedTracker tracking_profile15(
 826       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 827           "466432 IOThread::InitAsync::HttpNetorkSession::End"));
 828   globals_->proxy_script_fetcher_http_transaction_factory
 829       .reset(new net::HttpNetworkLayer(network_session.get()));
 830   TRACE_EVENT_END0("startup", "IOThread::InitAsync:HttpNetworkSession");
 831   scoped_ptr<net::URLRequestJobFactoryImpl> job_factory(
 832       new net::URLRequestJobFactoryImpl());
 833
 834   // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466432
 835   // is fixed.
 836   tracked_objects::ScopedTracker tracking_profile16(
 837       FROM_HERE_WITH_EXPLICIT_FUNCTION(
 838           "466432 IOThread::InitAsync::SetProtocolHandler"));
 839   job_factory->SetProtocolHandler(url::kDataScheme,
 840                                   new net::DataProtocolHandler());
 841   job_factory->SetProtocolHandler(
 842       url::kFileScheme,
 843       new net::FileProtocolHandler(
 844           content::BrowserThread::GetBlockingPool()->
 845               GetTaskRunnerWithShutdownBehavior(
 846                   base::SequencedWorkerPool::SKIP_ON_SHUTDOWN)));
 847 #if !defined(DISABLE_FTP_SUPPORT)
 848   globals_->proxy_script_fetcher_ftp_transaction_factory.reset(
 849       new net::FtpNetworkLayer(globals_->host_resolver.get()));
 850   job_factory->SetProtocolHandler(
 851       url::kFtpScheme,
 852       new net::FtpProtocolHandler(
 853           globals_->proxy_script_fetcher_ftp_transaction_factory.get()));
 854 #endif
 855   globals_->proxy_script_fetcher_url_request_job_factory = job_factory.Pass();
 856
 857   globals_->throttler_manager.reset(new net::URLRequestThrottlerManager());
 858   globals_->throttler_manager->set_net_log(net_log_);
 859   // Always done in production, disabled only for unit tests.
 860   globals_->throttler_manager->set_enable_thread_checks(true);
 861
 862   globals_->proxy_script_fetcher_context.reset(
 863       ConstructProxyScriptFetcherContext(globals_, net_log_));
 864
 865 #if defined(OS_MACOSX) && !defined(OS_IOS)
 866   // Start observing Keychain events. This needs to be done on the UI thread,
 867   // as Keychain services requires a CFRunLoop.
 868   BrowserThread::PostTask(BrowserThread::UI,
 869                           FROM_HERE,
 870                           base::Bind(&ObserveKeychainEvents));
 871 #endif
 872
 873   // InitSystemRequestContext turns right around and posts a task back
 874   // to the IO thread, so we can't let it run until we know the IO
 875   // thread has started.
 876   //
 877   // Note that since we are at BrowserThread::Init time, the UI thread
 878   // is blocked waiting for the thread to start.  Therefore, posting
 879   // this task to the main thread's message loop here is guaranteed to
 880   // get it onto the message loop while the IOThread object still
 881   // exists.  However, the message might not be processed on the UI
 882   // thread until after IOThread is gone, so use a weak pointer.
 883   BrowserThread::PostTask(BrowserThread::UI,
 884                           FROM_HERE,
 885                           base::Bind(&IOThread::InitSystemRequestContext,
 886                                      weak_factory_.GetWeakPtr()));
 887 }
 888
 889 void IOThread::CleanUp() {
 890   base::debug::LeakTracker<SafeBrowsingURLRequestContext>::CheckForLeaks();
 891
 892 #if defined(USE_NSS_CERTS) || defined(OS_IOS)
 893   net::ShutdownNSSHttpIO();
 894 #endif
 895
 896   system_url_request_context_getter_ = NULL;
 897
 898   // Release objects that the net::URLRequestContext could have been pointing
 899   // to.
 900
 901   // Shutdown the HistogramWatcher on the IO thread.
 902   net::NetworkChangeNotifier::ShutdownHistogramWatcher();
 903
 904   // This must be reset before the ChromeNetLog is destroyed.
 905   network_change_observer_.reset();
 906
 907   system_proxy_config_service_.reset();
 908
 909   delete globals_;
 910   globals_ = NULL;
 911
 912   base::debug::LeakTracker<SystemURLRequestContextGetter>::CheckForLeaks();
 913 }
 914
 915 void IOThread::InitializeNetworkOptions(const base::CommandLine& command_line) {
 916   // Only handle use-spdy command line flags if "spdy.disabled" preference is
 917   // not disabled via policy.
 918   if (is_spdy_disabled_by_policy_) {
 919     base::FieldTrial* trial = base::FieldTrialList::Find(kSpdyFieldTrialName);
 920     if (trial)
 921       trial->Disable();
 922   } else {
 923     std::string group = base::FieldTrialList::FindFullName(kSpdyFieldTrialName);
 924     VariationParameters params;
 925     if (!variations::GetVariationParams(kSpdyFieldTrialName, &params)) {
 926       params.clear();
 927     }
 928     ConfigureSpdyGlobals(command_line, group, params, globals_);
 929   }
 930
 931   ConfigureTCPFastOpen(command_line);
 932
 933   // TODO(rch): Make the client socket factory a per-network session
 934   // instance, constructed from a NetworkSession::Params, to allow us
 935   // to move this option to IOThread::Globals &
 936   // HttpNetworkSession::Params.
 937 }
 938
 939 void IOThread::ConfigureTCPFastOpen(const base::CommandLine& command_line) {
 940   const std::string trial_group =
 941       base::FieldTrialList::FindFullName(kTCPFastOpenFieldTrialName);
 942   if (trial_group == kTCPFastOpenHttpsEnabledGroupName)
 943     globals_->enable_tcp_fast_open_for_ssl.set(true);
 944   bool always_enable_if_supported =
 945       command_line.HasSwitch(switches::kEnableTcpFastOpen);
 946   // Check for OS support of TCP FastOpen, and turn it on for all connections
 947   // if indicated by user.
 948   net::CheckSupportAndMaybeEnableTCPFastOpen(always_enable_if_supported);
 949 }
 950
 951 // static
 952 void IOThread::ConfigureSpdyGlobals(
 953     const base::CommandLine& command_line,
 954     base::StringPiece spdy_trial_group,
 955     const VariationParameters& spdy_trial_params,
 956     IOThread::Globals* globals) {
 957   if (command_line.HasSwitch(switches::kTrustedSpdyProxy)) {
 958     globals->trusted_spdy_proxy.set(
 959         command_line.GetSwitchValueASCII(switches::kTrustedSpdyProxy));
 960   }
 961   if (command_line.HasSwitch(switches::kIgnoreUrlFetcherCertRequests))
 962     net::URLFetcher::SetIgnoreCertificateRequests(true);
 963
 964   if (command_line.HasSwitch(switches::kUseSpdy)) {
 965     std::string spdy_mode =
 966         command_line.GetSwitchValueASCII(switches::kUseSpdy);
 967     ConfigureSpdyGlobalsFromUseSpdyArgument(spdy_mode, globals);
 968     return;
 969   }
 970
 971   globals->next_protos.clear();
 972   globals->next_protos.push_back(net::kProtoHTTP11);
 973   bool enable_quic = false;
 974   globals->enable_quic.CopyToIfSet(&enable_quic);
 975   if (enable_quic) {
 976     globals->next_protos.push_back(net::kProtoQUIC1SPDY3);
 977   }
 978
 979   // No SPDY command-line flags have been specified. Examine trial groups.
 980   if (spdy_trial_group.starts_with(kSpdyFieldTrialHoldbackGroupNamePrefix)) {
 981     net::HttpStreamFactory::set_spdy_enabled(false);
 982     return;
 983   }
 984   if (spdy_trial_group.starts_with(kSpdyFieldTrialSpdy31GroupNamePrefix)) {
 985     globals->next_protos.push_back(net::kProtoSPDY31);
 986     globals->use_alternate_protocols.set(true);
 987     return;
 988   }
 989   if (spdy_trial_group.starts_with(kSpdyFieldTrialSpdy4GroupNamePrefix)) {
 990     globals->next_protos.push_back(net::kProtoSPDY31);
 991     globals->next_protos.push_back(net::kProtoSPDY4_14);
 992     globals->next_protos.push_back(net::kProtoSPDY4);
 993     globals->use_alternate_protocols.set(true);
 994     return;
 995   }
 996   if (spdy_trial_group.starts_with(kSpdyFieldTrialParametrizedPrefix)) {
 997     bool spdy_enabled = false;
 998     if (base::LowerCaseEqualsASCII(
 999             GetVariationParam(spdy_trial_params, "enable_spdy31"), "true")) {
1000       globals->next_protos.push_back(net::kProtoSPDY31);
1001       spdy_enabled = true;
1002     }
1003     if (base::LowerCaseEqualsASCII(
1004             GetVariationParam(spdy_trial_params, "enable_http2_14"), "true")) {
1005       globals->next_protos.push_back(net::kProtoSPDY4_14);
1006       spdy_enabled = true;
1007     }
1008     if (base::LowerCaseEqualsASCII(
1009             GetVariationParam(spdy_trial_params, "enable_http2"), "true")) {
1010       globals->next_protos.push_back(net::kProtoSPDY4);
1011       spdy_enabled = true;
1012     }
1013     // TODO(bnc): HttpStreamFactory::spdy_enabled_ is redundant with
1014     // globals->next_protos, can it be eliminated?
1015     net::HttpStreamFactory::set_spdy_enabled(spdy_enabled);
1016     globals->use_alternate_protocols.set(true);
1017     return;
1018   }
1019
1020   // By default, enable HTTP/2.
1021   globals->next_protos.push_back(net::kProtoSPDY31);
1022   globals->next_protos.push_back(net::kProtoSPDY4_14);
1023   globals->next_protos.push_back(net::kProtoSPDY4);
1024   globals->use_alternate_protocols.set(true);
1025 }
1026
1027 // static
1028 void IOThread::RegisterPrefs(PrefRegistrySimple* registry) {
1029   registry->RegisterStringPref(prefs::kAuthSchemes,
1030                                "basic,digest,ntlm,negotiate");
1031   registry->RegisterBooleanPref(prefs::kDisableAuthNegotiateCnameLookup, false);
1032   registry->RegisterBooleanPref(prefs::kEnableAuthNegotiatePort, false);
1033   registry->RegisterStringPref(prefs::kAuthServerWhitelist, std::string());
1034   registry->RegisterStringPref(prefs::kAuthNegotiateDelegateWhitelist,
1035                                std::string());
1036   registry->RegisterStringPref(prefs::kGSSAPILibraryName, std::string());
1037   registry->RegisterStringPref(
1038       data_reduction_proxy::prefs::kDataReductionProxy, std::string());
1039   registry->RegisterBooleanPref(prefs::kEnableReferrers, true);
1040   data_reduction_proxy::RegisterPrefs(registry);
1041   registry->RegisterBooleanPref(prefs::kBuiltInDnsClientEnabled, true);
1042   registry->RegisterBooleanPref(prefs::kQuickCheckEnabled, true);
1043 }
1044
1045 net::HttpAuthHandlerFactory* IOThread::CreateDefaultAuthHandlerFactory(
1046     net::HostResolver* resolver) {
1047   net::HttpAuthFilterWhitelist* auth_filter_default_credentials = NULL;
1048   if (!auth_server_whitelist_.empty()) {
1049     auth_filter_default_credentials =
1050         new net::HttpAuthFilterWhitelist(auth_server_whitelist_);
1051   }
1052   net::HttpAuthFilterWhitelist* auth_filter_delegate = NULL;
1053   if (!auth_delegate_whitelist_.empty()) {
1054     auth_filter_delegate =
1055         new net::HttpAuthFilterWhitelist(auth_delegate_whitelist_);
1056   }
1057   globals_->url_security_manager.reset(
1058       net::URLSecurityManager::Create(auth_filter_default_credentials,
1059                                       auth_filter_delegate));
1060   std::vector<std::string> supported_schemes;
1061   base::SplitString(auth_schemes_, ',', &supported_schemes);
1062
1063   scoped_ptr<net::HttpAuthHandlerRegistryFactory> registry_factory(
1064       net::HttpAuthHandlerRegistryFactory::Create(
1065           supported_schemes, globals_->url_security_manager.get(),
1066           resolver, gssapi_library_name_, negotiate_disable_cname_lookup_,
1067           negotiate_enable_port_));
1068   return registry_factory.release();
1069 }
1070
1071 void IOThread::ClearHostCache() {
1072   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
1073
1074   net::HostCache* host_cache = globals_->host_resolver->GetHostCache();
1075   if (host_cache)
1076     host_cache->clear();
1077 }
1078
1079 void IOThread::InitializeNetworkSessionParams(
1080     net::HttpNetworkSession::Params* params) {
1081   InitializeNetworkSessionParamsFromGlobals(*globals_, params);
1082 }
1083
1084 // static
1085 void IOThread::InitializeNetworkSessionParamsFromGlobals(
1086     const IOThread::Globals& globals,
1087     net::HttpNetworkSession::Params* params) {
1088   params->host_resolver = globals.host_resolver.get();
1089   params->cert_verifier = globals.cert_verifier.get();
1090   params->cert_policy_enforcer = globals.cert_policy_enforcer.get();
1091   params->channel_id_service = globals.system_channel_id_service.get();
1092   params->transport_security_state = globals.transport_security_state.get();
1093   params->ssl_config_service = globals.ssl_config_service.get();
1094   params->http_auth_handler_factory = globals.http_auth_handler_factory.get();
1095   params->http_server_properties =
1096       globals.http_server_properties->GetWeakPtr();
1097   params->network_delegate = globals.system_network_delegate.get();
1098   params->host_mapping_rules = globals.host_mapping_rules.get();
1099   params->ignore_certificate_errors = globals.ignore_certificate_errors;
1100   params->testing_fixed_http_port = globals.testing_fixed_http_port;
1101   params->testing_fixed_https_port = globals.testing_fixed_https_port;
1102   globals.enable_tcp_fast_open_for_ssl.CopyToIfSet(
1103       &params->enable_tcp_fast_open_for_ssl);
1104
1105   globals.initial_max_spdy_concurrent_streams.CopyToIfSet(
1106       &params->spdy_initial_max_concurrent_streams);
1107   globals.enable_spdy_compression.CopyToIfSet(
1108       &params->enable_spdy_compression);
1109   globals.enable_spdy_ping_based_connection_checking.CopyToIfSet(
1110       &params->enable_spdy_ping_based_connection_checking);
1111   globals.spdy_default_protocol.CopyToIfSet(
1112       &params->spdy_default_protocol);
1113   params->next_protos = globals.next_protos;
1114   globals.trusted_spdy_proxy.CopyToIfSet(&params->trusted_spdy_proxy);
1115   params->forced_spdy_exclusions = globals.forced_spdy_exclusions;
1116   globals.use_alternate_protocols.CopyToIfSet(
1117       &params->use_alternate_protocols);
1118   globals.alternative_service_probability_threshold.CopyToIfSet(
1119       &params->alternative_service_probability_threshold);
1120
1121   globals.enable_quic.CopyToIfSet(&params->enable_quic);
1122   globals.disable_insecure_quic.CopyToIfSet(&params->disable_insecure_quic);
1123   globals.enable_quic_for_proxies.CopyToIfSet(&params->enable_quic_for_proxies);
1124   globals.quic_always_require_handshake_confirmation.CopyToIfSet(
1125       &params->quic_always_require_handshake_confirmation);
1126   globals.quic_disable_connection_pooling.CopyToIfSet(
1127       &params->quic_disable_connection_pooling);
1128   globals.quic_load_server_info_timeout_srtt_multiplier.CopyToIfSet(
1129       &params->quic_load_server_info_timeout_srtt_multiplier);
1130   globals.quic_enable_connection_racing.CopyToIfSet(
1131       &params->quic_enable_connection_racing);
1132   globals.quic_enable_non_blocking_io.CopyToIfSet(
1133       &params->quic_enable_non_blocking_io);
1134   globals.quic_prefer_aes.CopyToIfSet(&params->quic_prefer_aes);
1135   globals.quic_disable_disk_cache.CopyToIfSet(
1136       &params->quic_disable_disk_cache);
1137   globals.quic_max_number_of_lossy_connections.CopyToIfSet(
1138       &params->quic_max_number_of_lossy_connections);
1139   globals.quic_packet_loss_threshold.CopyToIfSet(
1140       &params->quic_packet_loss_threshold);
1141   globals.quic_socket_receive_buffer_size.CopyToIfSet(
1142       &params->quic_socket_receive_buffer_size);
1143   globals.enable_quic_port_selection.CopyToIfSet(
1144       &params->enable_quic_port_selection);
1145   globals.quic_max_packet_length.CopyToIfSet(&params->quic_max_packet_length);
1146   globals.quic_user_agent_id.CopyToIfSet(&params->quic_user_agent_id);
1147   globals.quic_supported_versions.CopyToIfSet(
1148       &params->quic_supported_versions);
1149   params->quic_connection_options = globals.quic_connection_options;
1150
1151   globals.origin_to_force_quic_on.CopyToIfSet(
1152       &params->origin_to_force_quic_on);
1153   params->enable_user_alternate_protocol_ports =
1154       globals.enable_user_alternate_protocol_ports;
1155 }
1156
1157 base::TimeTicks IOThread::creation_time() const {
1158   return creation_time_;
1159 }
1160
1161 net::SSLConfigService* IOThread::GetSSLConfigService() {
1162   return ssl_config_service_manager_->Get();
1163 }
1164
1165 void IOThread::ChangedToOnTheRecordOnIOThread() {
1166   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
1167
1168   // Clear the host cache to avoid showing entries from the OTR session
1169   // in about:net-internals.
1170   ClearHostCache();
1171 }
1172
1173 void IOThread::InitSystemRequestContext() {
1174   if (system_url_request_context_getter_.get())
1175     return;
1176   // If we're in unit_tests, IOThread may not be run.
1177   if (!BrowserThread::IsMessageLoopValid(BrowserThread::IO))
1178     return;
1179   system_proxy_config_service_.reset(
1180       ProxyServiceFactory::CreateProxyConfigService(
1181           pref_proxy_config_tracker_.get()));
1182   system_url_request_context_getter_ =
1183       new SystemURLRequestContextGetter(this);
1184   // Safe to post an unretained this pointer, since IOThread is
1185   // guaranteed to outlive the IO BrowserThread.
1186   BrowserThread::PostTask(
1187       BrowserThread::IO,
1188       FROM_HERE,
1189       base::Bind(&IOThread::InitSystemRequestContextOnIOThread,
1190                  base::Unretained(this)));
1191 }
1192
1193 void IOThread::InitSystemRequestContextOnIOThread() {
1194   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
1195   DCHECK(!globals_->system_proxy_service.get());
1196   DCHECK(system_proxy_config_service_.get());
1197
1198   const base::CommandLine& command_line =
1199       *base::CommandLine::ForCurrentProcess();
1200   globals_->system_proxy_service.reset(
1201       ProxyServiceFactory::CreateProxyService(
1202           net_log_,
1203           globals_->proxy_script_fetcher_context.get(),
1204           globals_->system_network_delegate.get(),
1205           system_proxy_config_service_.release(),
1206           command_line,
1207           quick_check_enabled_.GetValue()));
1208
1209   net::HttpNetworkSession::Params system_params;
1210   InitializeNetworkSessionParams(&system_params);
1211   system_params.net_log = net_log_;
1212   system_params.proxy_service = globals_->system_proxy_service.get();
1213
1214   globals_->system_http_transaction_factory.reset(
1215       new net::HttpNetworkLayer(
1216           new net::HttpNetworkSession(system_params)));
1217   globals_->system_url_request_job_factory.reset(
1218       new net::URLRequestJobFactoryImpl());
1219   globals_->system_request_context.reset(
1220       ConstructSystemRequestContext(globals_, net_log_));
1221   globals_->system_request_context->set_ssl_config_service(
1222       globals_->ssl_config_service.get());
1223   globals_->system_request_context->set_http_server_properties(
1224       globals_->http_server_properties->GetWeakPtr());
1225 }
1226
1227 void IOThread::UpdateDnsClientEnabled() {
1228   globals()->host_resolver->SetDnsClientEnabled(*dns_client_enabled_);
1229 }
1230
1231 void IOThread::ConfigureQuic(const base::CommandLine& command_line) {
1232   // Always fetch the field trial group to ensure it is reported correctly.
1233   // The command line flags will be associated with a group that is reported
1234   // so long as trial is actually queried.
1235   std::string group =
1236       base::FieldTrialList::FindFullName(kQuicFieldTrialName);
1237   VariationParameters params;
1238   if (!variations::GetVariationParams(kQuicFieldTrialName, &params)) {
1239     params.clear();
1240   }
1241
1242   ConfigureQuicGlobals(command_line, group, params, is_quic_allowed_by_policy_,
1243                        globals_);
1244 }
1245
1246 // static
1247 void IOThread::ConfigureQuicGlobals(
1248     const base::CommandLine& command_line,
1249     base::StringPiece quic_trial_group,
1250     const VariationParameters& quic_trial_params,
1251     bool quic_allowed_by_policy,
1252     IOThread::Globals* globals) {
1253   bool enable_quic = ShouldEnableQuic(command_line, quic_trial_group,
1254                                       quic_allowed_by_policy);
1255   globals->enable_quic.set(enable_quic);
1256   bool enable_quic_for_proxies = ShouldEnableQuicForProxies(
1257       command_line, quic_trial_group, quic_allowed_by_policy);
1258   globals->enable_quic_for_proxies.set(enable_quic_for_proxies);
1259   if (enable_quic) {
1260     globals->disable_insecure_quic.set(
1261         ShouldDisableInsecureQuic(quic_trial_params));
1262     globals->quic_always_require_handshake_confirmation.set(
1263         ShouldQuicAlwaysRequireHandshakeConfirmation(quic_trial_params));
1264     globals->quic_disable_connection_pooling.set(
1265         ShouldQuicDisableConnectionPooling(quic_trial_params));
1266     int receive_buffer_size = GetQuicSocketReceiveBufferSize(quic_trial_params);
1267     if (receive_buffer_size != 0) {
1268       globals->quic_socket_receive_buffer_size.set(receive_buffer_size);
1269     }
1270     float load_server_info_timeout_srtt_multiplier =
1271         GetQuicLoadServerInfoTimeoutSrttMultiplier(quic_trial_params);
1272     if (load_server_info_timeout_srtt_multiplier != 0) {
1273       globals->quic_load_server_info_timeout_srtt_multiplier.set(
1274           load_server_info_timeout_srtt_multiplier);
1275     }
1276     globals->quic_enable_connection_racing.set(
1277         ShouldQuicEnableConnectionRacing(quic_trial_params));
1278     globals->quic_enable_non_blocking_io.set(
1279         ShouldQuicEnableNonBlockingIO(quic_trial_params));
1280     globals->quic_disable_disk_cache.set(
1281         ShouldQuicDisableDiskCache(quic_trial_params));
1282     globals->quic_prefer_aes.set(
1283         ShouldQuicPreferAes(quic_trial_params));
1284     int max_number_of_lossy_connections = GetQuicMaxNumberOfLossyConnections(
1285         quic_trial_params);
1286     if (max_number_of_lossy_connections != 0) {
1287       globals->quic_max_number_of_lossy_connections.set(
1288           max_number_of_lossy_connections);
1289     }
1290     float packet_loss_threshold = GetQuicPacketLossThreshold(quic_trial_params);
1291     if (packet_loss_threshold != 0)
1292       globals->quic_packet_loss_threshold.set(packet_loss_threshold);
1293     globals->enable_quic_port_selection.set(
1294         ShouldEnableQuicPortSelection(command_line));
1295     globals->quic_connection_options =
1296         GetQuicConnectionOptions(command_line, quic_trial_params);
1297   }
1298
1299   size_t max_packet_length = GetQuicMaxPacketLength(command_line,
1300                                                     quic_trial_params);
1301   if (max_packet_length != 0) {
1302     globals->quic_max_packet_length.set(max_packet_length);
1303   }
1304
1305   std::string quic_user_agent_id =
1306       chrome::VersionInfo::GetVersionStringModifier();
1307   if (!quic_user_agent_id.empty())
1308     quic_user_agent_id.push_back(' ');
1309   chrome::VersionInfo version_info;
1310   quic_user_agent_id.append(version_info.ProductNameAndVersionForUserAgent());
1311   globals->quic_user_agent_id.set(quic_user_agent_id);
1312
1313   net::QuicVersion version = GetQuicVersion(command_line, quic_trial_params);
1314   if (version != net::QUIC_VERSION_UNSUPPORTED) {
1315     net::QuicVersionVector supported_versions;
1316     supported_versions.push_back(version);
1317     globals->quic_supported_versions.set(supported_versions);
1318   }
1319
1320   double threshold = GetAlternativeProtocolProbabilityThreshold(
1321       command_line, quic_trial_params);
1322   if (threshold >=0 && threshold <= 1) {
1323     globals->alternative_service_probability_threshold.set(threshold);
1324     globals->http_server_properties->SetAlternativeServiceProbabilityThreshold(
1325         threshold);
1326   }
1327
1328   if (command_line.HasSwitch(switches::kOriginToForceQuicOn)) {
1329     net::HostPortPair quic_origin =
1330         net::HostPortPair::FromString(
1331             command_line.GetSwitchValueASCII(switches::kOriginToForceQuicOn));
1332     if (!quic_origin.IsEmpty()) {
1333       globals->origin_to_force_quic_on.set(quic_origin);
1334     }
1335   }
1336 }
1337
1338 bool IOThread::ShouldEnableQuic(const base::CommandLine& command_line,
1339                                 base::StringPiece quic_trial_group,
1340                                 bool quic_allowed_by_policy) {
1341   if (command_line.HasSwitch(switches::kDisableQuic) || !quic_allowed_by_policy)
1342     return false;
1343
1344   if (command_line.HasSwitch(switches::kEnableQuic))
1345     return true;
1346
1347   return quic_trial_group.starts_with(kQuicFieldTrialEnabledGroupName) ||
1348       quic_trial_group.starts_with(kQuicFieldTrialHttpsEnabledGroupName);
1349 }
1350
1351 // static
1352 bool IOThread::ShouldEnableQuicForProxies(const base::CommandLine& command_line,
1353                                           base::StringPiece quic_trial_group,
1354                                           bool quic_allowed_by_policy) {
1355   return ShouldEnableQuic(
1356       command_line, quic_trial_group, quic_allowed_by_policy) ||
1357       ShouldEnableQuicForDataReductionProxy();
1358 }
1359
1360 // static
1361 bool IOThread::ShouldEnableQuicForDataReductionProxy() {
1362   const base::CommandLine& command_line =
1363         *base::CommandLine::ForCurrentProcess();
1364
1365   if (command_line.HasSwitch(switches::kDisableQuic))
1366     return false;
1367
1368   return data_reduction_proxy::params::IsIncludedInQuicFieldTrial();
1369 }
1370
1371 // static
1372 bool IOThread::ShouldDisableInsecureQuic(
1373     const VariationParameters& quic_trial_params) {
1374   return base::LowerCaseEqualsASCII(
1375       GetVariationParam(quic_trial_params, "disable_insecure_quic"),
1376       "true");
1377 }
1378
1379 bool IOThread::ShouldEnableQuicPortSelection(
1380     const base::CommandLine& command_line) {
1381   if (command_line.HasSwitch(switches::kDisableQuicPortSelection))
1382     return false;
1383
1384   if (command_line.HasSwitch(switches::kEnableQuicPortSelection))
1385     return true;
1386
1387   return false;  // Default to disabling port selection on all channels.
1388 }
1389
1390 net::QuicTagVector IOThread::GetQuicConnectionOptions(
1391     const base::CommandLine& command_line,
1392     const VariationParameters& quic_trial_params) {
1393   if (command_line.HasSwitch(switches::kQuicConnectionOptions)) {
1394     return net::QuicUtils::ParseQuicConnectionOptions(
1395         command_line.GetSwitchValueASCII(switches::kQuicConnectionOptions));
1396   }
1397
1398   VariationParameters::const_iterator it =
1399       quic_trial_params.find("connection_options");
1400   if (it == quic_trial_params.end()) {
1401     return net::QuicTagVector();
1402   }
1403
1404   return net::QuicUtils::ParseQuicConnectionOptions(it->second);
1405 }
1406
1407 // static
1408 double IOThread::GetAlternativeProtocolProbabilityThreshold(
1409     const base::CommandLine& command_line,
1410     const VariationParameters& quic_trial_params) {
1411   double value;
1412   if (command_line.HasSwitch(
1413           switches::kAlternativeServiceProbabilityThreshold)) {
1414     if (base::StringToDouble(
1415             command_line.GetSwitchValueASCII(
1416                 switches::kAlternativeServiceProbabilityThreshold),
1417             &value)) {
1418       return value;
1419     }
1420   }
1421   if (command_line.HasSwitch(switches::kEnableQuic)) {
1422     return 0;
1423   }
1424   // TODO(bnc): Remove when new parameter name rolls out and server
1425   // configuration is changed.
1426   if (base::StringToDouble(
1427           GetVariationParam(quic_trial_params,
1428                             "alternate_protocol_probability_threshold"),
1429           &value)) {
1430     return value;
1431   }
1432   if (base::StringToDouble(
1433           GetVariationParam(quic_trial_params,
1434                             "alternative_service_probability_threshold"),
1435           &value)) {
1436     return value;
1437   }
1438   return -1;
1439 }
1440
1441 // static
1442 bool IOThread::ShouldQuicAlwaysRequireHandshakeConfirmation(
1443     const VariationParameters& quic_trial_params) {
1444   return base::LowerCaseEqualsASCII(
1445       GetVariationParam(quic_trial_params,
1446                         "always_require_handshake_confirmation"),
1447       "true");
1448 }
1449
1450 // static
1451 bool IOThread::ShouldQuicDisableConnectionPooling(
1452     const VariationParameters& quic_trial_params) {
1453   return base::LowerCaseEqualsASCII(
1454       GetVariationParam(quic_trial_params, "disable_connection_pooling"),
1455       "true");
1456 }
1457
1458 // static
1459 float IOThread::GetQuicLoadServerInfoTimeoutSrttMultiplier(
1460     const VariationParameters& quic_trial_params) {
1461   double value;
1462   if (base::StringToDouble(GetVariationParam(quic_trial_params,
1463                                              "load_server_info_time_to_srtt"),
1464                            &value)) {
1465     return (float)value;
1466   }
1467   return 0.0f;
1468 }
1469
1470 // static
1471 bool IOThread::ShouldQuicEnableConnectionRacing(
1472     const VariationParameters& quic_trial_params) {
1473   return base::LowerCaseEqualsASCII(
1474       GetVariationParam(quic_trial_params, "enable_connection_racing"),
1475       "true");
1476 }
1477
1478 // static
1479 bool IOThread::ShouldQuicEnableNonBlockingIO(
1480     const VariationParameters& quic_trial_params) {
1481   return base::LowerCaseEqualsASCII(
1482       GetVariationParam(quic_trial_params, "enable_non_blocking_io"),
1483       "true");
1484 }
1485
1486 // static
1487 bool IOThread::ShouldQuicDisableDiskCache(
1488     const VariationParameters& quic_trial_params) {
1489   return base::LowerCaseEqualsASCII(
1490       GetVariationParam(quic_trial_params, "disable_disk_cache"), "true");
1491 }
1492
1493 // static
1494 bool IOThread::ShouldQuicPreferAes(
1495     const VariationParameters& quic_trial_params) {
1496   return base::LowerCaseEqualsASCII(
1497       GetVariationParam(quic_trial_params, "prefer_aes"), "true");
1498 }
1499
1500 // static
1501 int IOThread::GetQuicMaxNumberOfLossyConnections(
1502     const VariationParameters& quic_trial_params) {
1503   int value;
1504   if (base::StringToInt(GetVariationParam(quic_trial_params,
1505                                           "max_number_of_lossy_connections"),
1506                         &value)) {
1507     return value;
1508   }
1509   return 0;
1510 }
1511
1512 // static
1513 float IOThread::GetQuicPacketLossThreshold(
1514     const VariationParameters& quic_trial_params) {
1515   double value;
1516   if (base::StringToDouble(GetVariationParam(quic_trial_params,
1517                                              "packet_loss_threshold"),
1518                            &value)) {
1519     return (float)value;
1520   }
1521   return 0.0f;
1522 }
1523
1524 // static
1525 int IOThread::GetQuicSocketReceiveBufferSize(
1526     const VariationParameters& quic_trial_params) {
1527   int value;
1528   if (base::StringToInt(GetVariationParam(quic_trial_params,
1529                                           "receive_buffer_size"),
1530                         &value)) {
1531     return value;
1532   }
1533   return 0;
1534 }
1535
1536 // static
1537 size_t IOThread::GetQuicMaxPacketLength(
1538     const base::CommandLine& command_line,
1539     const VariationParameters& quic_trial_params) {
1540   if (command_line.HasSwitch(switches::kQuicMaxPacketLength)) {
1541     unsigned value;
1542     if (!base::StringToUint(
1543             command_line.GetSwitchValueASCII(switches::kQuicMaxPacketLength),
1544             &value)) {
1545       return 0;
1546     }
1547     return value;
1548   }
1549
1550   unsigned value;
1551   if (base::StringToUint(GetVariationParam(quic_trial_params,
1552                                            "max_packet_length"),
1553                          &value)) {
1554     return value;
1555   }
1556   return 0;
1557 }
1558
1559 // static
1560 net::QuicVersion IOThread::GetQuicVersion(
1561     const base::CommandLine& command_line,
1562     const VariationParameters& quic_trial_params) {
1563   if (command_line.HasSwitch(switches::kQuicVersion)) {
1564     return ParseQuicVersion(
1565         command_line.GetSwitchValueASCII(switches::kQuicVersion));
1566   }
1567
1568   return ParseQuicVersion(GetVariationParam(quic_trial_params, "quic_version"));
1569 }
1570
1571 // static
1572 net::QuicVersion IOThread::ParseQuicVersion(const std::string& quic_version) {
1573   net::QuicVersionVector supported_versions = net::QuicSupportedVersions();
1574   for (size_t i = 0; i < supported_versions.size(); ++i) {
1575     net::QuicVersion version = supported_versions[i];
1576     if (net::QuicVersionToString(version) == quic_version) {
1577       return version;
1578     }
1579   }
1580
1581   return net::QUIC_VERSION_UNSUPPORTED;
1582 }