Disable proxy config button and show banner if proxy prefs are managed.

chrome/chrome_browser.gypi

 # Copyright (c) 2010 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': [
     {
       'target_name': 'browser',
       'type': '<(library)',
       'msvs_guid': '5BF908A7-68FB-4A4B-99E3-8C749F1FE4EA',
@@ skipping 2018 matching lines @@
         'browser/possible_url_model.cc',
         'browser/possible_url_model.h',
         'browser/power_save_blocker.h',
         'browser/power_save_blocker_common.cc',
         'browser/power_save_blocker_stub.cc',
         'browser/power_save_blocker_win.cc',
         'browser/pref_member.cc',
         'browser/pref_member.h',
         'browser/pref_service.cc',
         'browser/pref_service.h',
+        'browser/pref_set_observer.cc',
+        'browser/pref_set_observer.h',
         'browser/pref_value_store.cc',
         'browser/pref_value_store.h',
         'browser/preferences_mac.cc',
         'browser/preferences_mac.h',
         'browser/printing/print_dialog_gtk.cc',
         'browser/printing/print_dialog_gtk.h',
         'browser/printing/print_dialog_cloud.cc',
         'browser/printing/print_dialog_cloud.h',
         'browser/printing/print_job.cc',
         'browser/printing/print_job.h',
@@ skipping 1622 matching lines @@
       ],
     },
   ],
 }
 
 # Local Variables:
 # tab-width:2
 # indent-tabs-mode:nil
 # End:
 # vim: set expandtab tabstop=2 shiftwidth=2: