Enforce the 'requirements' field in manifests.

chrome/chrome_common.gypi

 # Copyright (c) 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.
 
 {
   'targets': [
     {
       'target_name': 'common',
       'type': 'static_library',
       'variables': {
@@ skipping 166 matching lines @@
         'common/extensions/matcher/url_matcher_helpers.cc',
         'common/extensions/matcher/url_matcher_helpers.h',
         'common/extensions/permissions/api_permission.cc',
         'common/extensions/permissions/api_permission.h',
         'common/extensions/permissions/permission_message.cc',
         'common/extensions/permissions/permission_message.h',
         'common/extensions/permissions/permission_set.cc',
         'common/extensions/permissions/permission_set.h',
         'common/extensions/permissions/permissions_info.cc',
         'common/extensions/permissions/permissions_info.h',
+        'common/extensions/requirements_provider.h',
         'common/extensions/update_manifest.cc',
         'common/extensions/update_manifest.h',
         'common/extensions/url_pattern.cc',
         'common/extensions/url_pattern.h',
         'common/extensions/url_pattern_set.cc',
         'common/extensions/url_pattern_set.h',
         'common/extensions/user_script.cc',
         'common/extensions/user_script.h',
         'common/extensions/api/extension_api.cc',
         'common/extensions/api/extension_api.h',
@@ skipping 339 matching lines @@
         'common/metrics/proto/user_action_event.proto',
       ],
       'variables': {
         'proto_in_dir': 'common/metrics/proto',
         'proto_out_dir': 'chrome/common/metrics/proto',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }