Warn user in case extension delays network traffic too much.

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 1281 matching lines @@
         'browser/extensions/extension_settings_storage_cache_unittest.cc',
         'browser/extensions/extension_settings_storage_unittest.h',
         'browser/extensions/extension_settings_storage_unittest.cc',
         'browser/extensions/extension_settings_sync_unittest.cc',
         'browser/extensions/extension_service_unittest.cc',
         'browser/extensions/extension_service_unittest.h',
         'browser/extensions/extension_special_storage_policy_unittest.cc',
         'browser/extensions/extension_sync_data_unittest.cc',
         'browser/extensions/extension_ui_unittest.cc',
         'browser/extensions/extension_updater_unittest.cc',
+        'browser/extensions/extension_warning_set_unittest.cc',
         'browser/extensions/extension_webnavigation_unittest.cc',
         'browser/extensions/extension_webrequest_api_unittest.cc',
         'browser/extensions/extension_webrequest_time_tracker_unittest.cc',
         'browser/extensions/extensions_quota_service_unittest.cc',
         'browser/extensions/external_policy_extension_loader_unittest.cc',
         'browser/extensions/file_reader_unittest.cc',
         'browser/extensions/image_loading_tracker_unittest.cc',
         'browser/extensions/in_memory_extension_settings_storage_unittest.cc',
         'browser/extensions/key_identifier_conversion_views_unittest.cc',
         'browser/extensions/sandboxed_extension_unpacker_unittest.cc',
@@ skipping 2733 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'
 }