Add private system extension API to get system update status

chrome/chrome_browser.gypi

 # Copyright (c) 2011 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',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 363 matching lines @@
         'browser/chrome_page_zoom.cc',
         'browser/chrome_page_zoom.h',
         'browser/chrome_plugin_message_filter.cc',
         'browser/chrome_plugin_message_filter.h',
         'browser/chrome_plugin_service_filter.cc',
         'browser/chrome_plugin_service_filter.h',
         'browser/chrome_quota_permission_context.cc',
         'browser/chrome_quota_permission_context.h',
         'browser/chromeos/accessibility/system_event_observer.cc',
         'browser/chromeos/accessibility/system_event_observer.h',
+        'browser/chromeos/accessibility/accessibility_private_extension_api.cc',
+        'browser/chromeos/accessibility/accessibility_private_extension_api.h',
         'browser/chromeos/accessibility/accessibility_util.cc',
         'browser/chromeos/accessibility/accessibility_util.h',
         'browser/chromeos/audio_handler.cc',
         'browser/chromeos/audio_handler.h',
         'browser/chromeos/audio_mixer.h',
         'browser/chromeos/audio_mixer_alsa.cc',
         'browser/chromeos/audio_mixer_alsa.h',
         'browser/chromeos/bluetooth/bluetooth_adapter.cc',
         'browser/chromeos/bluetooth/bluetooth_adapter.h',
         'browser/chromeos/bluetooth/bluetooth_device.cc',
@@ skipping 4858 matching lines @@
       'type': 'static_library',
       'sources': [ 'browser/history/in_memory_url_index_cache.proto' ],
       'variables': {
         'proto_in_dir': 'browser/history',
         'proto_out_dir': 'chrome/browser/history',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }