Remove //chrome dependency from ExtensionPrefs

chrome/chrome_browser_extensions.gypi

 # Copyright (c) 2013 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_extensions',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 171 matching lines @@
         'browser/extensions/api/command_line_private/command_line_private_api.cc',
         'browser/extensions/api/command_line_private/command_line_private_api.h',
         'browser/extensions/api/commands/command_service.cc',
         'browser/extensions/api/commands/command_service.h',
         'browser/extensions/api/content_settings/content_settings_api.cc',
         'browser/extensions/api/content_settings/content_settings_api.h',
         'browser/extensions/api/content_settings/content_settings_api_constants.cc',
         'browser/extensions/api/content_settings/content_settings_api_constants.h',
         'browser/extensions/api/content_settings/content_settings_helpers.cc',
         'browser/extensions/api/content_settings/content_settings_helpers.h',
+        'browser/extensions/api/content_settings/content_settings_service.cc',
+        'browser/extensions/api/content_settings/content_settings_service.h',
         'browser/extensions/api/content_settings/content_settings_store.cc',
         'browser/extensions/api/content_settings/content_settings_store.h',
         'browser/extensions/api/commands/commands.cc',
         'browser/extensions/api/commands/commands.h',
         'browser/extensions/api/context_menus/context_menus_api.cc',
         'browser/extensions/api/context_menus/context_menus_api.h',
         'browser/extensions/api/context_menus/context_menus_api_helpers.cc',
         'browser/extensions/api/context_menus/context_menus_api_helpers.h',
         'browser/extensions/api/cookies/cookies_api.cc',
         'browser/extensions/api/cookies/cookies_api.h',
@@ skipping 984 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/extensions/api/cast_channel/cast_channel.proto' ],
       'variables': {
           'proto_in_dir': 'browser/extensions/api/cast_channel',
           'proto_out_dir': 'chrome/browser/extensions/api/cast_channel',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],  # 'conditions'
 }