Create a mechanism define declarative rules via the extension manifest.

extensions/extensions.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.
 
 {
   'variables': {
     'extensions_common_constants_sources': [
       'common/constants.cc',
       'common/constants.h',
     ],
     'extensions_common_mojo_sources': [
       'common/mojo/keep_alive.mojom',
       'common/mojo/stash.mojom',
     ],
     'extensions_common_sources': [
       'common/api/bluetooth/bluetooth_manifest_data.cc',
       'common/api/bluetooth/bluetooth_manifest_data.h',
       'common/api/bluetooth/bluetooth_manifest_handler.cc',
       'common/api/bluetooth/bluetooth_manifest_handler.h',
       'common/api/bluetooth/bluetooth_manifest_permission.cc',
       'common/api/bluetooth/bluetooth_manifest_permission.h',
+      'common/api/declarative/declarative_manifest_data.cc',
+      'common/api/declarative/declarative_manifest_data.h',
+      'common/api/declarative/declarative_manifest_handler.cc',
+      'common/api/declarative/declarative_manifest_handler.h',
       'common/api/messaging/message.h',
       'common/api/printer_provider/usb_printer_manifest_data.cc',
       'common/api/printer_provider/usb_printer_manifest_data.h',
       'common/api/printer_provider/usb_printer_manifest_handler.cc',
       'common/api/printer_provider/usb_printer_manifest_handler.h',
       'common/api/sockets/sockets_manifest_data.cc',
       'common/api/sockets/sockets_manifest_data.h',
       'common/api/sockets/sockets_manifest_handler.cc',
       'common/api/sockets/sockets_manifest_handler.h',
       'common/api/sockets/sockets_manifest_permission.cc',
@@ skipping 1014 matching lines @@
       'test/result_catcher.h',
       'test/test_content_utility_client.cc',
       'test/test_content_utility_client.h',
       'test/test_extensions_client.cc',
       'test/test_extensions_client.h',
       'test/test_permission_message_provider.cc',
       'test/test_permission_message_provider.h',
     ],
   },
 }