Use URLRequestContextBuilderMojo to create the SystemURLRequestContext.

chrome/browser/io_thread.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_IO_THREAD_H_
 #define CHROME_BROWSER_IO_THREAD_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 69 matching lines @@
 class HostResolver;
 class HttpAuthHandlerFactory;
 class HttpAuthPreferences;
 class LoggingNetworkChangeObserver;
 class NetworkQualityEstimator;
 class ProxyConfigService;
 class RTTAndThroughputEstimatesObserver;
 class SSLConfigService;
 class URLRequestContext;
 class URLRequestContextGetter;
-class URLRequestContextStorage;
 
 namespace ct {
 class STHObserver;
 }
 
 }  // namespace net
 
 namespace net_log {
 class ChromeNetLog;
 }
@@ skipping 33 matching lines @@
     // Global aggregator of data use. It must outlive the
     // |system_network_delegate|.
     std::unique_ptr<data_usage::DataUseAggregator> data_use_aggregator;
 #if defined(OS_ANDROID)
     // An external observer of data use.
     std::unique_ptr<chrome::android::ExternalDataUseObserver>
         external_data_use_observer;
 #endif  // defined(OS_ANDROID)
     std::vector<scoped_refptr<const net::CTLogVerifier>> ct_logs;
     std::unique_ptr<net::HttpAuthPreferences> http_auth_preferences;
-    std::unique_ptr<net::URLRequestContextStorage>
-        system_request_context_storage;
     std::unique_ptr<net::URLRequestContext> system_request_context;
     SystemRequestContextLeakChecker system_request_context_leak_checker;
 #if BUILDFLAG(ENABLE_EXTENSIONS)
     scoped_refptr<extensions::EventRouterForwarder>
         extension_event_router_forwarder;
 #endif
     std::unique_ptr<net::HostMappingRules> host_mapping_rules;
     std::unique_ptr<net::NetworkQualityEstimator> network_quality_estimator;
     std::unique_ptr<net::RTTAndThroughputEstimatesObserver>
         network_quality_observer;
@@ skipping 191 matching lines @@
   bool http_09_on_non_default_ports_enabled_;
 
   const base::TimeTicks creation_time_;
 
   base::WeakPtrFactory<IOThread> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IOThread);
 };
 
 #endif  // CHROME_BROWSER_IO_THREAD_H_