Make iOS's IOThread class use URLRequestContextBuilder.

ios/components/io_thread/ios_io_thread.h

Index: ios/components/io_thread/ios_io_thread.h
diff --git a/ios/components/io_thread/ios_io_thread.h b/ios/components/io_thread/ios_io_thread.h
index adad232eb7dbbbafc7df03ad8407b18df2edf768..438636a474c94dd849ad0bddefb461be0e4cc592 100644
--- a/ios/components/io_thread/ios_io_thread.h
+++ b/ios/components/io_thread/ios_io_thread.h
@@ -29,25 +29,10 @@ class PrefProxyConfigTracker;
 class PrefService;
 
 namespace net {
-class CTPolicyEnforcer;
-class CertVerifier;
-class ChannelIDService;
-class CookieStore;
-class CTVerifier;
-class HostResolver;
-class HttpAuthHandlerFactory;
-class HttpAuthPreferences;
-class HttpServerProperties;
-class HttpTransactionFactory;
-class HttpUserAgentSettings;
 class NetworkDelegate;
 class ProxyConfigService;
-class ProxyService;
-class SSLConfigService;
-class TransportSecurityState;
 class URLRequestContext;
 class URLRequestContextGetter;
-class URLRequestJobFactory;
 }  // namespace net
 
 namespace net_log {
@@ -98,32 +83,13 @@ class IOSIOThread : public web::WebThreadDelegate {
     Globals();
     ~Globals();
 
-    // The "system" NetworkDelegate, used for BrowserState-agnostic network
-    // events.
-    std::unique_ptr<net::NetworkDelegate> system_network_delegate;
-    std::unique_ptr<net::HostResolver> host_resolver;
     std::unique_ptr<net::CertVerifier> cert_verifier;
     // The ChannelIDService must outlive the HttpTransactionFactory.
     std::unique_ptr<net::ChannelIDService> system_channel_id_service;
-    // This TransportSecurityState doesn't load or save any state. It's only
-    // used to enforce pinning for system requests and will only use built-in
-    // pins.
-    std::unique_ptr<net::TransportSecurityState> transport_security_state;
     std::unique_ptr<net::CTVerifier> cert_transparency_verifier;
     scoped_refptr<net::SSLConfigService> ssl_config_service;
-    std::unique_ptr<net::HttpAuthPreferences> http_auth_preferences;
-    std::unique_ptr<net::HttpAuthHandlerFactory> http_auth_handler_factory;
-    std::unique_ptr<net::HttpServerProperties> http_server_properties;
-    std::unique_ptr<net::ProxyService> system_proxy_service;
-    std::unique_ptr<net::HttpNetworkSession> system_http_network_session;
-    std::unique_ptr<net::HttpTransactionFactory>
-        system_http_transaction_factory;
-    std::unique_ptr<net::URLRequestJobFactory> system_url_request_job_factory;
     std::unique_ptr<net::URLRequestContext> system_request_context;
     SystemRequestContextLeakChecker system_request_context_leak_checker;
-    std::unique_ptr<net::CookieStore> system_cookie_store;
-    std::unique_ptr<net::HttpUserAgentSettings> http_user_agent_settings;
-    std::unique_ptr<net::CTPolicyEnforcer> ct_policy_enforcer;
   };
 
   // |net_log| must either outlive the IOSIOThread or be NULL.
@@ -177,20 +143,12 @@ class IOSIOThread : public web::WebThreadDelegate {
   void Init() override;
   void CleanUp() override;
 
-  // Sets up HttpAuthPreferences and HttpAuthHandlerFactory on Globals.
-  void CreateDefaultAuthHandlerFactory();
-
   // Returns an SSLConfigService instance.
   net::SSLConfigService* GetSSLConfigService();
 
   // Discards confidental data. To be called on IO thread only.
   void ChangedToOnTheRecordOnIOThread();
 
-  static net::URLRequestContext* ConstructSystemRequestContext(
-      Globals* globals,
-      const net::HttpNetworkSession::Params& params,
-      net::NetLog* net_log);
-
   // The NetLog is owned by the application context, to allow logging from other
   // threads during shutdown, but is used most frequently on the IO thread.
   net_log::ChromeNetLog* net_log_;