Add extensions code to use common updater in components/update_client/

extensions/extensions.gyp

 # Copyright 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.
 
 {
   'includes': [
     'extensions.gypi',
   ],
   'variables': {
     'chromium_code': 1,
@@ skipping 117 matching lines @@
         '../components/components.gyp:browsing_data',
         '../components/components.gyp:device_event_log_component',
         '../components/components.gyp:guest_view_browser',
         '../components/components.gyp:keyed_service_content',
         '../components/components.gyp:keyed_service_core',
         '../components/components.gyp:onc_component',
         '../components/components.gyp:pref_registry',
         '../components/components.gyp:sessions_content',
         '../components/components.gyp:storage_monitor',
         '../components/components.gyp:ui_zoom',
+        '../components/components.gyp:update_client',
         '../components/components.gyp:variations',
         '../components/components.gyp:web_cache_browser',
         '../components/components.gyp:web_modal',
         '../content/content.gyp:content_browser',
         '../device/bluetooth/bluetooth.gyp:device_bluetooth',
         '../device/serial/serial.gyp:device_serial',
         '../google_apis/google_apis.gyp:google_apis',
         '../skia/skia.gyp:skia',
         '../third_party/leveldatabase/leveldatabase.gyp:leveldatabase',
         '../third_party/re2/re2.gyp:re2',
@@ skipping 171 matching lines @@
               '<(SHARED_INTERMEDIATE_DIR)/blink/devtools_resources.pak',
             ],
             'pak_output': '<(PRODUCT_DIR)/extensions_shell_and_test.pak',
           },
           'includes': [ '../build/repack_action.gypi' ],
         },
       ],
     },
   ]
 }