Take 2 at implementing activeTab.

chrome/chrome_tests.gypi

 # Copyright (c) 2012 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',
       'common/pref_names.cc',
@@ skipping 1151 matching lines @@
         'browser/diagnostics/diagnostics_model_unittest.cc',
         'browser/download/chrome_download_manager_delegate_unittest.cc',
         'browser/download/download_item_model_unittest.cc',
         'browser/download/download_request_infobar_delegate_unittest.cc',
         'browser/download/download_request_limiter_unittest.cc',
         'browser/download/download_shelf_unittest.cc',
         'browser/download/download_status_updater_unittest.cc',
         'browser/enumerate_modules_model_unittest_win.cc',
         'browser/event_disposition.cc',
         'browser/event_disposition.h',
+        'browser/extensions/active_tab_unittest.cc',
         'browser/extensions/admin_policy_unittest.cc',
         'browser/extensions/api/alarms/alarms_api_unittest.cc',
         'browser/extensions/api/content_settings/content_settings_store_unittest.cc',
         'browser/extensions/api/content_settings/content_settings_unittest.cc',
         'browser/extensions/api/cookies/cookies_unittest.cc',
         'browser/extensions/api/declarative/initializing_rules_registry_unittest.cc',
         'browser/extensions/api/declarative/rules_registry_service_unittest.cc',
         'browser/extensions/api/discovery/discovery_api_unittest.cc',
         'browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc',
         'browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc',
@@ skipping 3475 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'
 }