Make the hcsm and its providers communicate via an observer interface.

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 1335 matching lines @@
         'browser/chromeos/system/name_value_pairs_parser_unittest.cc',
         'browser/chromeos/network_message_observer_unittest.cc',
         'browser/chromeos/notifications/desktop_notifications_unittest.cc',
         'browser/chromeos/offline/offline_load_page_unittest.cc',
         'browser/chromeos/proxy_config_service_impl_unittest.cc',
         'browser/chromeos/status/input_method_menu_unittest.cc',
         'browser/chromeos/system/mock_statistics_provider.cc',
         'browser/chromeos/system/mock_statistics_provider.h',
         'browser/chromeos/version_loader_unittest.cc',
         'browser/command_updater_unittest.cc',
+        'browser/content_settings/content_settings_mock_observer.cc',
+        'browser/content_settings/content_settings_mock_observer.h',        
         'browser/content_settings/content_settings_mock_provider.cc',
         'browser/content_settings/content_settings_mock_provider.h',
         'browser/content_settings/content_settings_origin_identifier_value_map_unittest.cc',
         'browser/content_settings/content_settings_pattern_unittest.cc',
         'browser/content_settings/content_settings_pattern_parser_unittest.cc',
         'browser/content_settings/content_settings_policy_provider_unittest.cc',
         'browser/content_settings/content_settings_pref_provider_unittest.cc',
         'browser/content_settings/content_settings_provider_unittest.cc',
         'browser/content_settings/host_content_settings_map_unittest.cc',
         'browser/content_settings/mock_settings_observer.cc',
@@ skipping 2784 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'
 }