Add proxy_config component

chrome/browser/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//third_party/protobuf/proto_library.gni")
 
@@ skipping 111 matching lines @@
     "//components/mime_util",
     "//components/navigation_metrics",
     "//components/network_time",
     "//components/offline_pages",
     "//components/omnibox",
     "//components/os_crypt",
     "//components/packed_ct_ev_whitelist",
     "//components/password_manager/core/browser",
     "//components/password_manager/core/common",
     "//components/policy:policy_component",
+    "//components/proxy_config",
     "//components/query_parser",
     "//components/rappor",
     "//components/renderer_context_menu",
     "//components/search",
     "//components/search_engines",
     "//components/search_provider_logos",
     "//components/signin/core/browser",
     "//components/startup_metric_utils",
     "//components/strings",
     "//components/suggestions",
@@ skipping 1044 matching lines @@
     ]
   }
 
   if (enable_wifi_bootstrapping) {
     sources += [
       "local_discovery/wifi/mock_wifi_manager.cc",
       "local_discovery/wifi/mock_wifi_manager.h",
     ]
   }
 }