Supervised user blacklist: Add downloader class to download a blacklist if needed.

chrome/chrome_browser.gypi

 # Copyright 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.
 
 {
   'variables': {
     # All .cc, .h, .m, and .mm files under browser except for:
     # * tests and mocks.
     # * code below browser/chromeos
     # * code below browser/extensions
@@ skipping 2246 matching lines @@
       'browser/chrome_device_client.cc',
       'browser/chrome_device_client.h',
     ],
     'chrome_browser_supervised_user_sources': [
       'browser/supervised_user/custodian_profile_downloader_service.cc',
       'browser/supervised_user/custodian_profile_downloader_service.h',
       'browser/supervised_user/custodian_profile_downloader_service_factory.cc',
       'browser/supervised_user/custodian_profile_downloader_service_factory.h',
       'browser/supervised_user/experimental/supervised_user_blacklist.cc',
       'browser/supervised_user/experimental/supervised_user_blacklist.h',
+      'browser/supervised_user/experimental/supervised_user_blacklist_downloader.cc',
+      'browser/supervised_user/experimental/supervised_user_blacklist_downloader.h',
       'browser/supervised_user/permission_request_creator.h',
       'browser/supervised_user/permission_request_creator_apiary.cc',
       'browser/supervised_user/permission_request_creator_apiary.h',
       'browser/supervised_user/permission_request_creator_sync.cc',
       'browser/supervised_user/permission_request_creator_sync.h',
       'browser/supervised_user/supervised_user_constants.cc',
       'browser/supervised_user/supervised_user_constants.h',
       'browser/supervised_user/supervised_user_interstitial.cc',
       'browser/supervised_user/supervised_user_interstitial.h',
       'browser/supervised_user/supervised_user_navigation_observer.cc',
@@ skipping 1317 matching lines @@
           'variables': {
             'proto_in_dir': 'browser/sync_file_system/drive_backend',
             'proto_out_dir': 'chrome/browser/sync_file_system/drive_backend',
           },
           'includes': [ '../build/protoc.gypi' ]
         },
       ],
     },],
   ],
 }