Componentize proxy code from chrome/browser/net

components/proxy_config.gypi

 # Copyright 2015 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.
 
 {
   'targets': [
     {
       # GN version: //components/proxy_config
       'target_name': 'proxy_config',
       'type': '<(component)',
       'dependencies': [
         '../base/base.gyp:base',
         '../net/net.gyp:net',
       ],
       'include_dirs': [
         '..',
       ],
       'defines': [
         'PROXY_CONFIG_IMPLEMENTATION',
       ],
       'sources': [
+        'proxy_config/pref_proxy_config_tracker.cc',
+        'proxy_config/pref_proxy_config_tracker.h',
+        'proxy_config/pref_proxy_config_tracker_impl.cc',
+        'proxy_config/pref_proxy_config_tracker_impl.h',
         'proxy_config/proxy_config_dictionary.cc',
         'proxy_config/proxy_config_dictionary.h',
         'proxy_config/proxy_config_export.h',
         'proxy_config/proxy_prefs.cc',
         'proxy_config/proxy_prefs.h',
       ],
     },
   ],
 }