Use URLRequestContextBuilderMojo to create the SystemURLRequestContext.

chromeos/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//third_party/protobuf/proto_library.gni")
 
 assert(is_chromeos, "Non-ChromeOS builds must not depend on //chromeos")
 
@@ skipping 303 matching lines @@
     "network/certificate_pattern.cc",
     "network/certificate_pattern.h",
     "network/client_cert_resolver.cc",
     "network/client_cert_resolver.h",
     "network/client_cert_util.cc",
     "network/client_cert_util.h",
     "network/device_state.cc",
     "network/device_state.h",
     "network/dhcp_proxy_script_fetcher_chromeos.cc",
     "network/dhcp_proxy_script_fetcher_chromeos.h",
+    "network/dhcp_proxy_script_fetcher_factory_chromeos.cc",
+    "network/dhcp_proxy_script_fetcher_factory_chromeos.h",
     "network/firewall_hole.cc",
     "network/firewall_hole.h",
     "network/geolocation_handler.cc",
     "network/geolocation_handler.h",
     "network/host_resolver_impl_chromeos.cc",
     "network/host_resolver_impl_chromeos.h",
     "network/managed_network_configuration_handler.cc",
     "network/managed_network_configuration_handler.h",
     "network/managed_network_configuration_handler_impl.cc",
     "network/managed_network_configuration_handler_impl.h",
@@ skipping 457 matching lines @@
   proto_out_dir = "chromeos/dbus/biod"
 }
 
 proto_library("media_perception_proto") {
   sources = [
     "dbus/proto/media_perception.proto",
   ]
 
   proto_out_dir = "chromeos/media_perception"
 }