Use FakeDesktopMediaList for Desktop Capture API tests.

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 121 matching lines @@
         'browser/extensions/test_extension_prefs.cc',
         'browser/extensions/test_extension_prefs.h',
         'browser/extensions/test_extension_service.cc',
         'browser/extensions/test_extension_service.h',
         'browser/extensions/test_extension_system.cc',
         'browser/extensions/test_extension_system.h',
         'browser/google_apis/dummy_auth_service.cc',
         'browser/google_apis/dummy_auth_service.h',
         'browser/google_apis/test_util.cc',
         'browser/google_apis/test_util.h',
+        'browser/media/fake_desktop_media_list.cc',
+        'browser/media/fake_desktop_media_list.h',
         'browser/media_galleries/media_galleries_test_util.cc',
         'browser/media_galleries/media_galleries_test_util.h',
         'browser/net/dns_probe_test_util.cc',
         'browser/net/dns_probe_test_util.h',
         'browser/net/url_request_mock_util.cc',
         'browser/net/url_request_mock_util.h',
         'browser/notifications/notification_test_util.cc',
         'browser/notifications/notification_test_util.h',
         'browser/password_manager/mock_password_store.cc',
         'browser/password_manager/mock_password_store.h',
@@ skipping 2780 matching lines @@
             'browser/ui/app_list/test/fake_profile_store.cc',
             'browser/ui/app_list/test/fake_profile_store.h',
             'browser/ui/app_list/test/fast_show_pickler_unittest.cc',
             'browser/ui/views/app_list/win/app_list_win_unittest.cc',
           ],
         },
       ],
     }],
   ],  # 'conditions'
 }