chromeos: Remove UpdateObserver, which has been unused for long.

chrome/chrome_tests.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.
 
 {
   'variables' : {
     'pyautolib_sources': [
       'app/chrome_command_ids.h',
       'app/chrome_dll_resource.h',
       'common/automation_constants.h',
@@ skipping 2314 matching lines @@
         'browser/chromeos/media/media_player_browsertest.cc',
         'browser/chromeos/notifications/notification_browsertest.cc',
         'browser/chromeos/panels/panel_browsertest.cc',
         'browser/chromeos/status/accessibility_menu_button_browsertest.cc',
         'browser/chromeos/status/caps_lock_menu_button_browsertest.cc',
         'browser/chromeos/status/clock_menu_button_browsertest.cc',
         'browser/chromeos/status/input_method_menu_button_browsertest.cc',
         'browser/chromeos/status/power_menu_button_browsertest.cc',
         'browser/chromeos/status/status_area_view_browsertest.cc',
         'browser/chromeos/tab_closeable_state_watcher_browsertest.cc',
-        'browser/chromeos/update_browsertest.cc',
         'browser/content_settings/content_settings_browsertest.cc',
         'browser/crash_recovery_browsertest.cc',
         'browser/custom_handlers/protocol_handler_registry_browsertest.cc',
         'browser/download/download_browsertest.cc',
         'browser/download/save_page_browsertest.cc',
         'browser/errorpage_browsertest.cc',
         'browser/extensions/alert_apitest.cc',
         'browser/extensions/all_urls_apitest.cc',
         'browser/extensions/app_background_page_apitest.cc',
         'browser/extensions/app_process_apitest.cc',
@@ skipping 1722 matching lines @@
               # Use outputs of this action as inputs for the main target build.
               # Seems as a misnomer but makes this happy on Linux (scons).
               'process_outputs_as_sources': 1,
             },
           ],  # 'actions'
         },
       ]
     }],  # 'coverage!=0'
   ],  # 'conditions'
 }