Move common functionality of IOSChromeIOThread to ios/components.

ios/chrome/browser/ios_chrome_io_thread.mm

Index: ios/chrome/browser/ios_chrome_io_thread.mm
diff --git a/ios/chrome/browser/ios_chrome_io_thread.mm b/ios/chrome/browser/ios_chrome_io_thread.mm
index 9508c6766973e378ad7091c575461713a3224c2b..1d6a4875ba113bc7e1e2dd3659b81871502aeb70 100644
--- a/ios/chrome/browser/ios_chrome_io_thread.mm
+++ b/ios/chrome/browser/ios_chrome_io_thread.mm
@@ -4,574 +4,27 @@
 
 #include "ios/chrome/browser/ios_chrome_io_thread.h"
 
-#include <stddef.h>
-
-#include <utility>
-#include <vector>
-
-#include "base/bind.h"
-#include "base/bind_helpers.h"
-#include "base/command_line.h"
-#include "base/compiler_specific.h"
-#include "base/debug/leak_tracker.h"
-#include "base/environment.h"
-#include "base/logging.h"
-#include "base/macros.h"
 #include "base/memory/ptr_util.h"
-#include "base/metrics/field_trial.h"
-#include "base/single_thread_task_runner.h"
-#include "base/stl_util.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_split.h"
-#include "base/strings/string_util.h"
-#include "base/threading/sequenced_worker_pool.h"
-#include "base/threading/thread.h"
-#include "base/time/time.h"
-#include "base/trace_event/trace_event.h"
-#include "components/net_log/chrome_net_log.h"
-#include "components/network_session_configurator/network_session_configurator.h"
-#include "components/prefs/pref_service.h"
-#include "components/proxy_config/ios/proxy_service_factory.h"
-#include "components/proxy_config/pref_proxy_config_tracker.h"
-#include "components/variations/variations_associated_data.h"
-#include "components/version_info/version_info.h"
-#include "ios/chrome/browser/chrome_switches.h"
-#include "ios/chrome/browser/net/cookie_util.h"
 #include "ios/chrome/browser/net/ios_chrome_network_delegate.h"
 #include "ios/chrome/common/channel_info.h"
-#include "ios/web/public/user_agent.h"
-#include "ios/web/public/web_client.h"
-#include "ios/web/public/web_thread.h"
-#include "net/base/sdch_manager.h"
-#include "net/cert/cert_verifier.h"
-#include "net/cert/ct_known_logs.h"
-#include "net/cert/ct_log_verifier.h"
-#include "net/cert/ct_policy_enforcer.h"
-#include "net/cert/ct_verifier.h"
-#include "net/cert/multi_log_ct_verifier.h"
-#include "net/cert/multi_threaded_cert_verifier.h"
-#include "net/cookies/cookie_monster.h"
-#include "net/cookies/cookie_store.h"
-#include "net/dns/host_cache.h"
-#include "net/dns/host_resolver.h"
-#include "net/dns/mapped_host_resolver.h"
-#include "net/http/http_auth_filter.h"
-#include "net/http/http_auth_handler_factory.h"
-#include "net/http/http_auth_preferences.h"
-#include "net/http/http_network_layer.h"
-#include "net/http/http_server_properties_impl.h"
-#include "net/log/net_log_event_type.h"
-#include "net/nqe/external_estimate_provider.h"
-#include "net/nqe/network_quality_estimator.h"
-#include "net/proxy/proxy_config_service.h"
-#include "net/proxy/proxy_script_fetcher_impl.h"
-#include "net/proxy/proxy_service.h"
-#include "net/socket/tcp_client_socket.h"
-#include "net/spdy/chromium/spdy_session.h"
-#include "net/ssl/channel_id_service.h"
-#include "net/ssl/default_channel_id_store.h"
-#include "net/url_request/data_protocol_handler.h"
-#include "net/url_request/file_protocol_handler.h"
-#include "net/url_request/static_http_user_agent_settings.h"
-#include "net/url_request/url_request_context.h"
-#include "net/url_request/url_request_context_builder.h"
-#include "net/url_request/url_request_context_getter.h"
-#include "net/url_request/url_request_job_factory_impl.h"
-#include "url/url_constants.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
-// The IOSChromeIOThread object must outlive any tasks posted to the IO thread
-// before the Quit task, so base::Bind() calls are not refcounted.
-
-namespace {
-
-const char kSupportedAuthSchemes[] = "basic,digest,ntlm";
-
-// Field trial for network quality estimator. Seeds RTT and downstream
-// throughput observations with values that correspond to the connection type
-// determined by the operating system.
-const char kNetworkQualityEstimatorFieldTrialName[] = "NetworkQualityEstimator";
-
-// Used for the "system" URLRequestContext.
-class SystemURLRequestContext : public net::URLRequestContext {
- public:
-  SystemURLRequestContext() {
-  }
-
- private:
-  ~SystemURLRequestContext() override {
-    AssertNoURLRequests();
-  }
-};
-
-std::unique_ptr<net::HostResolver> CreateGlobalHostResolver(
-    net::NetLog* net_log) {
-  TRACE_EVENT0("startup", "IOSChromeIOThread::CreateGlobalHostResolver");
-  const base::CommandLine& command_line =
-      *base::CommandLine::ForCurrentProcess();
-
-  std::unique_ptr<net::HostResolver> global_host_resolver =
-      net::HostResolver::CreateSystemResolver(net::HostResolver::Options(),
-                                              net_log);
-
-  // If hostname remappings were specified on the command-line, layer these
-  // rules on top of the real host resolver. This allows forwarding all requests
-  // through a designated test server.
-  if (!command_line.HasSwitch(switches::kIOSHostResolverRules))
-    return global_host_resolver;
-
-  std::unique_ptr<net::MappedHostResolver> remapped_resolver(
-      new net::MappedHostResolver(std::move(global_host_resolver)));
-  remapped_resolver->SetRulesFromString(
-      command_line.GetSwitchValueASCII(switches::kIOSHostResolverRules));
-  // TODO(crbug.com/703565): remove std::move() once Xcode 9.0+ is required.
-  return std::move(remapped_resolver);
-}
-
-int GetSwitchValueAsInt(const base::CommandLine& command_line,
-                        const std::string& switch_name) {
-  int value;
-  if (!base::StringToInt(command_line.GetSwitchValueASCII(switch_name),
-                         &value)) {
-    return 0;
-  }
-  return value;
-}
-
-}  // namespace
-
-class IOSChromeIOThread::LoggingNetworkChangeObserver
-    : public net::NetworkChangeNotifier::IPAddressObserver,
-      public net::NetworkChangeNotifier::ConnectionTypeObserver,
-      public net::NetworkChangeNotifier::NetworkChangeObserver {
- public:
-  // |net_log| must remain valid throughout our lifetime.
-  explicit LoggingNetworkChangeObserver(net::NetLog* net_log)
-      : net_log_(net_log) {
-    net::NetworkChangeNotifier::AddIPAddressObserver(this);
-    net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
-    net::NetworkChangeNotifier::AddNetworkChangeObserver(this);
-  }
-
-  ~LoggingNetworkChangeObserver() override {
-    net::NetworkChangeNotifier::RemoveIPAddressObserver(this);
-    net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
-    net::NetworkChangeNotifier::RemoveNetworkChangeObserver(this);
-  }
-
-  // NetworkChangeNotifier::IPAddressObserver implementation.
-  void OnIPAddressChanged() override {
-    VLOG(1) << "Observed a change to the network IP addresses";
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_IP_ADDRESSES_CHANGED);
-  }
-
-  // NetworkChangeNotifier::ConnectionTypeObserver implementation.
-  void OnConnectionTypeChanged(
-      net::NetworkChangeNotifier::ConnectionType type) override {
-    std::string type_as_string =
-        net::NetworkChangeNotifier::ConnectionTypeToString(type);
-
-    VLOG(1) << "Observed a change to network connectivity state "
-            << type_as_string;
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_CONNECTIVITY_CHANGED,
-        net::NetLog::StringCallback("new_connection_type", &type_as_string));
-  }
-
-  // NetworkChangeNotifier::NetworkChangeObserver implementation.
-  void OnNetworkChanged(
-      net::NetworkChangeNotifier::ConnectionType type) override {
-    std::string type_as_string =
-        net::NetworkChangeNotifier::ConnectionTypeToString(type);
-
-    VLOG(1) << "Observed a network change to state " << type_as_string;
-
-    net_log_->AddGlobalEntry(
-        net::NetLogEventType::NETWORK_CHANGED,
-        net::NetLog::StringCallback("new_connection_type", &type_as_string));
-  }
-
- private:
-  net::NetLog* net_log_;
-  DISALLOW_COPY_AND_ASSIGN(LoggingNetworkChangeObserver);
-};
-
-class SystemURLRequestContextGetter : public net::URLRequestContextGetter {
- public:
-  explicit SystemURLRequestContextGetter(IOSChromeIOThread* io_thread);
-
-  // Implementation for net::UrlRequestContextGetter.
-  net::URLRequestContext* GetURLRequestContext() override;
-  scoped_refptr<base::SingleThreadTaskRunner> GetNetworkTaskRunner()
-      const override;
-
-  // Tells the getter that the URLRequestContext is about to be shut down.
-  void Shutdown();
-
- protected:
-  ~SystemURLRequestContextGetter() override;
-
- private:
-  IOSChromeIOThread* io_thread_;  // Weak pointer, owned by ApplicationContext.
-  scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
-
-  base::debug::LeakTracker<SystemURLRequestContextGetter> leak_tracker_;
-};
-
-SystemURLRequestContextGetter::SystemURLRequestContextGetter(
-    IOSChromeIOThread* io_thread)
-    : io_thread_(io_thread),
-      network_task_runner_(
-          web::WebThread::GetTaskRunnerForThread(web::WebThread::IO)) {}
-
-SystemURLRequestContextGetter::~SystemURLRequestContextGetter() {}
-
-net::URLRequestContext* SystemURLRequestContextGetter::GetURLRequestContext() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-  if (!io_thread_)
-    return nullptr;
-  DCHECK(io_thread_->globals()->system_request_context.get());
-
-  return io_thread_->globals()->system_request_context.get();
-}
-
-scoped_refptr<base::SingleThreadTaskRunner>
-SystemURLRequestContextGetter::GetNetworkTaskRunner() const {
-  return network_task_runner_;
-}
-
-void SystemURLRequestContextGetter::Shutdown() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-  io_thread_ = nullptr;
-  NotifyContextShuttingDown();
-}
-
-IOSChromeIOThread::Globals::SystemRequestContextLeakChecker::
-    SystemRequestContextLeakChecker(Globals* globals)
-    : globals_(globals) {
-  DCHECK(globals_);
-}
-
-IOSChromeIOThread::Globals::SystemRequestContextLeakChecker::
-    ~SystemRequestContextLeakChecker() {
-  if (globals_->system_request_context.get())
-    globals_->system_request_context->AssertNoURLRequests();
-}
-
-IOSChromeIOThread::Globals::Globals()
-    : system_request_context_leak_checker(this) {}
-
-IOSChromeIOThread::Globals::~Globals() {}
-
-// |local_state| is passed in explicitly in order to (1) reduce implicit
-// dependencies and (2) make IOSChromeIOThread more flexible for testing.
 IOSChromeIOThread::IOSChromeIOThread(PrefService* local_state,
                                      net_log::ChromeNetLog* net_log)
-    : net_log_(net_log),
-      globals_(nullptr),
-      creation_time_(base::TimeTicks::Now()),
-      weak_factory_(this) {
-  pref_proxy_config_tracker_ =
-      ProxyServiceFactory::CreatePrefProxyConfigTrackerOfLocalState(
-          local_state);
+    : IOSIOThread(local_state, net_log) {
   IOSChromeNetworkDelegate::InitializePrefsOnUIThread(nullptr, local_state);
-  ssl_config_service_manager_.reset(
-      ssl_config::SSLConfigServiceManager::CreateDefaultManager(
-          local_state,
-          web::WebThread::GetTaskRunnerForThread(web::WebThread::IO)));
-
-  web::WebThread::SetDelegate(web::WebThread::IO, this);
-}
-
-IOSChromeIOThread::~IOSChromeIOThread() {
-  // This isn't needed for production code, but in tests, IOSChromeIOThread may
-  // be multiply constructed.
-  web::WebThread::SetDelegate(web::WebThread::IO, nullptr);
-
-  pref_proxy_config_tracker_->DetachFromPrefService();
-  DCHECK(!globals_);
-}
-
-IOSChromeIOThread::Globals* IOSChromeIOThread::globals() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-  return globals_;
 }
 
-void IOSChromeIOThread::SetGlobalsForTesting(Globals* globals) {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-  DCHECK(!globals || !globals_);
-  globals_ = globals;
-}
+IOSChromeIOThread::~IOSChromeIOThread() = default;
 
-net_log::ChromeNetLog* IOSChromeIOThread::net_log() {
-  return net_log_;
+std::unique_ptr<net::NetworkDelegate>
+IOSChromeIOThread::CreateSystemNetworkDelegate() {
+  return base::MakeUnique<IOSChromeNetworkDelegate>();
 }
 
-void IOSChromeIOThread::ChangedToOnTheRecord() {
-  DCHECK_CURRENTLY_ON(web::WebThread::UI);
-  web::WebThread::PostTask(
-      web::WebThread::IO, FROM_HERE,
-      base::Bind(&IOSChromeIOThread::ChangedToOnTheRecordOnIOThread,
-                 base::Unretained(this)));
-}
-
-net::URLRequestContextGetter*
-IOSChromeIOThread::system_url_request_context_getter() {
-  DCHECK_CURRENTLY_ON(web::WebThread::UI);
-  if (!system_url_request_context_getter_.get()) {
-    InitSystemRequestContext();
-  }
-  return system_url_request_context_getter_.get();
-}
-
-void IOSChromeIOThread::Init() {
-  TRACE_EVENT0("startup", "IOSChromeIOThread::Init");
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-
-  const base::CommandLine& command_line =
-      *base::CommandLine::ForCurrentProcess();
-
-  DCHECK(!globals_);
-  globals_ = new Globals;
-
-  // Add an observer that will emit network change events to the ChromeNetLog.
-  // Assuming NetworkChangeNotifier dispatches in FIFO order, we should be
-  // logging the network change before other IO thread consumers respond to it.
-  network_change_observer_.reset(new LoggingNetworkChangeObserver(net_log_));
-
-  // Setup the HistogramWatcher to run on the IO thread.
-  net::NetworkChangeNotifier::InitHistogramWatcher();
-
-  std::unique_ptr<IOSChromeNetworkDelegate> chrome_network_delegate(
-      new IOSChromeNetworkDelegate());
-
-  globals_->system_network_delegate = std::move(chrome_network_delegate);
-  globals_->host_resolver = CreateGlobalHostResolver(net_log_);
-
-  std::map<std::string, std::string> network_quality_estimator_params;
-  variations::GetVariationParams(kNetworkQualityEstimatorFieldTrialName,
-                                 &network_quality_estimator_params);
-
-  std::unique_ptr<net::ExternalEstimateProvider> external_estimate_provider;
-  // Pass ownership.
-  globals_->network_quality_estimator.reset(new net::NetworkQualityEstimator(
-      std::move(external_estimate_provider), network_quality_estimator_params,
-      net_log_));
-
-  globals_->cert_verifier = net::CertVerifier::CreateDefault();
-
-  globals_->transport_security_state.reset(new net::TransportSecurityState());
-
-  std::vector<scoped_refptr<const net::CTLogVerifier>> ct_logs(
-      net::ct::CreateLogVerifiersForKnownLogs());
-
-  net::MultiLogCTVerifier* ct_verifier = new net::MultiLogCTVerifier();
-  globals_->cert_transparency_verifier.reset(ct_verifier);
-  // Add built-in logs
-  ct_verifier->AddLogs(ct_logs);
-
-  globals_->ct_policy_enforcer.reset(new net::CTPolicyEnforcer());
-
-  globals_->ssl_config_service = GetSSLConfigService();
-
-  CreateDefaultAuthHandlerFactory();
-  globals_->http_server_properties.reset(new net::HttpServerPropertiesImpl());
-  // In-memory cookie store.
-  globals_->system_cookie_store.reset(new net::CookieMonster(nullptr, nullptr));
-  // In-memory channel ID store.
-  globals_->system_channel_id_service.reset(
-      new net::ChannelIDService(new net::DefaultChannelIDStore(nullptr)));
-  globals_->system_cookie_store->SetChannelIDServiceID(
-      globals_->system_channel_id_service->GetUniqueID());
-  globals_->http_user_agent_settings.reset(new net::StaticHttpUserAgentSettings(
-      std::string(),
-      web::GetWebClient()->GetUserAgent(web::UserAgentType::MOBILE)));
-  if (command_line.HasSwitch(switches::kIOSTestingFixedHttpPort)) {
-    params_.testing_fixed_http_port =
-        GetSwitchValueAsInt(command_line, switches::kIOSTestingFixedHttpPort);
-  }
-  if (command_line.HasSwitch(switches::kIOSTestingFixedHttpsPort)) {
-    params_.testing_fixed_https_port =
-        GetSwitchValueAsInt(command_line, switches::kIOSTestingFixedHttpsPort);
-  }
-
-  params_.ignore_certificate_errors = false;
-  params_.enable_user_alternate_protocol_ports = false;
-
-  std::string quic_user_agent_id = ::GetChannelString();
-  if (!quic_user_agent_id.empty())
-    quic_user_agent_id.push_back(' ');
-  quic_user_agent_id.append(
-      version_info::GetProductNameAndVersionForUserAgent());
-  quic_user_agent_id.push_back(' ');
-  quic_user_agent_id.append(web::BuildOSCpuInfo());
-
-  network_session_configurator::ParseFieldTrials(
-      /*is_quic_force_disabled=*/false,
-      /*is_quic_force_enabled=*/false, quic_user_agent_id, &params_);
-
-  // InitSystemRequestContext turns right around and posts a task back
-  // to the IO thread, so we can't let it run until we know the IO
-  // thread has started.
-  //
-  // Note that since we are at WebThread::Init time, the UI thread
-  // is blocked waiting for the thread to start.  Therefore, posting
-  // this task to the main thread's message loop here is guaranteed to
-  // get it onto the message loop while the IOSChromeIOThread object still
-  // exists.  However, the message might not be processed on the UI
-  // thread until after IOSChromeIOThread is gone, so use a weak pointer.
-  web::WebThread::PostTask(
-      web::WebThread::UI, FROM_HERE,
-      base::Bind(&IOSChromeIOThread::InitSystemRequestContext,
-                 weak_factory_.GetWeakPtr()));
-}
-
-void IOSChromeIOThread::CleanUp() {
-  system_url_request_context_getter_->Shutdown();
-  system_url_request_context_getter_ = nullptr;
-
-  // Release objects that the net::URLRequestContext could have been pointing
-  // to.
-
-  // Shutdown the HistogramWatcher on the IO thread.
-  net::NetworkChangeNotifier::ShutdownHistogramWatcher();
-
-  // This must be reset before the ChromeNetLog is destroyed.
-  network_change_observer_.reset();
-
-  system_proxy_config_service_.reset();
-
-  delete globals_;
-  globals_ = nullptr;
-
-  base::debug::LeakTracker<SystemURLRequestContextGetter>::CheckForLeaks();
-}
-
-void IOSChromeIOThread::CreateDefaultAuthHandlerFactory() {
-  std::vector<std::string> supported_schemes =
-      base::SplitString(kSupportedAuthSchemes, ",", base::TRIM_WHITESPACE,
-                        base::SPLIT_WANT_NONEMPTY);
-  globals_->http_auth_preferences.reset(
-      new net::HttpAuthPreferences(supported_schemes, std::string()));
-  globals_->http_auth_handler_factory =
-      net::HttpAuthHandlerRegistryFactory::Create(
-          globals_->http_auth_preferences.get(), globals_->host_resolver.get());
-}
-
-void IOSChromeIOThread::ClearHostCache() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-
-  net::HostCache* host_cache = globals_->host_resolver->GetHostCache();
-  if (host_cache)
-    host_cache->clear();
-}
-
-const net::HttpNetworkSession::Params& IOSChromeIOThread::NetworkSessionParams()
-    const {
-  return params_;
-}
-
-base::TimeTicks IOSChromeIOThread::creation_time() const {
-  return creation_time_;
-}
-
-net::SSLConfigService* IOSChromeIOThread::GetSSLConfigService() {
-  return ssl_config_service_manager_->Get();
-}
-
-void IOSChromeIOThread::ChangedToOnTheRecordOnIOThread() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-
-  // Clear the host cache to avoid showing entries from the OTR session
-  // in about:net-internals.
-  ClearHostCache();
-}
-
-void IOSChromeIOThread::InitSystemRequestContext() {
-  if (system_url_request_context_getter_.get())
-    return;
-  // If we're in unit_tests, IOSChromeIOThread may not be run.
-  if (!web::WebThread::IsMessageLoopValid(web::WebThread::IO))
-    return;
-  system_proxy_config_service_ = ProxyServiceFactory::CreateProxyConfigService(
-      pref_proxy_config_tracker_.get());
-
-  system_url_request_context_getter_ = new SystemURLRequestContextGetter(this);
-  // Safe to post an unretained this pointer, since IOSChromeIOThread is
-  // guaranteed to outlive the IO WebThread.
-  web::WebThread::PostTask(
-      web::WebThread::IO, FROM_HERE,
-      base::Bind(&IOSChromeIOThread::InitSystemRequestContextOnIOThread,
-                 base::Unretained(this)));
-}
-
-void IOSChromeIOThread::InitSystemRequestContextOnIOThread() {
-  DCHECK_CURRENTLY_ON(web::WebThread::IO);
-  DCHECK(!globals_->system_proxy_service.get());
-  DCHECK(system_proxy_config_service_.get());
-
-  globals_->system_proxy_service = ProxyServiceFactory::CreateProxyService(
-      net_log_, nullptr, globals_->system_network_delegate.get(),
-      std::move(system_proxy_config_service_), true /* quick_check_enabled */);
-
-  globals_->system_request_context.reset(
-      ConstructSystemRequestContext(globals_, params_, net_log_));
-}
-
-net::URLRequestContext* IOSChromeIOThread::ConstructSystemRequestContext(
-    IOSChromeIOThread::Globals* globals,
-    const net::HttpNetworkSession::Params& params,
-    net::NetLog* net_log) {
-  net::URLRequestContext* context = new SystemURLRequestContext;
-  context->set_net_log(net_log);
-  context->set_host_resolver(globals->host_resolver.get());
-  context->set_cert_verifier(globals->cert_verifier.get());
-  context->set_transport_security_state(
-      globals->transport_security_state.get());
-  context->set_cert_transparency_verifier(
-      globals->cert_transparency_verifier.get());
-  context->set_ssl_config_service(globals->ssl_config_service.get());
-  context->set_http_auth_handler_factory(
-      globals->http_auth_handler_factory.get());
-  context->set_proxy_service(globals->system_proxy_service.get());
-  context->set_ct_policy_enforcer(globals->ct_policy_enforcer.get());
-
-  net::URLRequestJobFactoryImpl* system_job_factory =
-      new net::URLRequestJobFactoryImpl();
-  // Data URLs are always loaded through the system request context on iOS
-  // (due to UIWebView limitations).
-  bool set_protocol = system_job_factory->SetProtocolHandler(
-      url::kDataScheme, base::MakeUnique<net::DataProtocolHandler>());
-  DCHECK(set_protocol);
-  globals->system_url_request_job_factory.reset(system_job_factory);
-  context->set_job_factory(globals->system_url_request_job_factory.get());
-
-  context->set_cookie_store(globals->system_cookie_store.get());
-  context->set_channel_id_service(globals->system_channel_id_service.get());
-  context->set_network_delegate(globals->system_network_delegate.get());
-  context->set_http_user_agent_settings(
-      globals->http_user_agent_settings.get());
-  context->set_network_quality_estimator(
-      globals->network_quality_estimator.get());
-
-  context->set_http_server_properties(globals->http_server_properties.get());
-
-  net::HttpNetworkSession::Params system_params(params);
-  net::URLRequestContextBuilder::SetHttpNetworkSessionComponents(
-      context, &system_params);
-
-  globals->system_http_network_session.reset(
-      new net::HttpNetworkSession(system_params));
-  globals->system_http_transaction_factory.reset(
-      new net::HttpNetworkLayer(globals->system_http_network_session.get()));
-  context->set_http_transaction_factory(
-      globals->system_http_transaction_factory.get());
-
-  return context;
+std::string IOSChromeIOThread::GetChannelString() const {
+  return ::GetChannelString();
 }