Make DisplayInfoProvider an interface

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 902 matching lines @@
         'browser/extensions/api/socket/tcp_socket_unittest.cc',
         'browser/extensions/api/socket/tls_socket_unittest.cc',
         'browser/extensions/api/socket/udp_socket_unittest.cc',
         'browser/extensions/api/sockets_tcp/sockets_tcp_api_unittest.cc',
         'browser/extensions/api/sockets_tcp_server/sockets_tcp_server_api_unittest.cc',
         'browser/extensions/api/sockets_udp/sockets_udp_api_unittest.cc',
         'browser/extensions/api/storage/policy_value_store_unittest.cc',
         'browser/extensions/api/storage/settings_sync_unittest.cc',
         'browser/extensions/api/streams_private/streams_private_manifest_unittest.cc',
         'browser/extensions/api/synced_notifications_private/synced_notifications_shim_unittest.cc',
-        'browser/extensions/api/system_display/display_info_provider_chromeos_unittest.cc',
         'browser/extensions/api/web_navigation/frame_navigation_state_unittest.cc',
         'browser/extensions/api/web_request/form_data_parser_unittest.cc',
         'browser/extensions/api/web_request/upload_data_presenter_unittest.cc',
         'browser/extensions/api/web_request/web_request_api_unittest.cc',
         'browser/extensions/api/web_request/web_request_permissions_unittest.cc',
         'browser/extensions/api/web_request/web_request_time_tracker_unittest.cc',
         'browser/extensions/app_sync_data_unittest.cc',
         'browser/extensions/blacklist_state_fetcher_unittest.cc',
         'browser/extensions/bookmark_app_helper_unittest.cc',
         'browser/extensions/browser_permissions_policy_delegate_unittest.cc',
         'browser/extensions/chrome_app_sorting_unittest.cc',
         'browser/extensions/chrome_component_extension_resource_manager_unittest.cc',
         'browser/extensions/component_loader_unittest.cc',
         'browser/extensions/convert_user_script_unittest.cc',
         'browser/extensions/convert_web_app_unittest.cc',
         'browser/extensions/default_apps_unittest.cc',
+        'browser/extensions/display_info_provider_chromeos_unittest.cc',
         'browser/extensions/error_console/error_console_unittest.cc',
         'browser/extensions/event_router_forwarder_unittest.cc',
         'browser/extensions/extension_api_unittest.cc',
         'browser/extensions/extension_api_unittest.h',
         'browser/extensions/extension_action_icon_factory_unittest.cc',
         'browser/extensions/extension_action_manager_unittest.cc',
         'browser/extensions/extension_action_unittest.cc',
         'browser/extensions/extension_context_menu_model_unittest.cc',
         'browser/extensions/extension_creator_filter_unittest.cc',
         'browser/extensions/extension_error_controller_unittest.cc',
@@ skipping 1938 matching lines @@
               'dependencies': [
                 '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
               ],
             }],
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }