Introduce a Factory for Declarative API objects that performs deduping

chrome/chrome_tests_unit.gypi

 # Copyright 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.
 {
   'targets': [
     {
       # This target contains mocks and test utilities that don't belong in
       # production libraries but are used by more than one test executable.
       'target_name': 'test_support_common',
       'type': 'static_library',
@@ skipping 694 matching lines @@
         'browser/extensions/activity_database_unittest.cc',
         'browser/extensions/activity_log_unittest.cc',
         'browser/extensions/admin_policy_unittest.cc',
         'browser/extensions/api/alarms/alarms_api_unittest.cc',
         'browser/extensions/api/api_resource_manager_unittest.cc',
         'browser/extensions/api/bluetooth/bluetooth_event_router_unittest.cc',
         'browser/extensions/api/bookmarks/bookmark_api_helpers_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/deduping_factory_unittest.cc',
         'browser/extensions/api/declarative/declarative_rule_unittest.cc',
         'browser/extensions/api/declarative/initializing_rules_registry_unittest.cc',
         'browser/extensions/api/declarative/rules_registry_service_unittest.cc',
         'browser/extensions/api/declarative/rules_registry_with_cache_unittest.cc',
         'browser/extensions/api/declarative_content/content_action_unittest.cc',
         'browser/extensions/api/declarative_content/content_condition_unittest.cc',
         'browser/extensions/api/declarative_content/content_rules_registry_unittest.cc',
         'browser/extensions/api/declarative_webrequest/webrequest_action_unittest.cc',
         'browser/extensions/api/declarative_webrequest/webrequest_condition_attribute_unittest.cc',
         'browser/extensions/api/declarative_webrequest/webrequest_condition_unittest.cc',
@@ skipping 1747 matching lines @@
               # more details.
               'DebugInformationFormat': '3',
               'ProgramDataBaseFileName': '<(PRODUCT_DIR)/unit_tests.exe.pdb',
             },
           },
         },
       ],
     }],
   ],  # 'conditions'
 }