Add a browser test which checks if the 'Caps Lock by pressing both Shift keys' feature is working.

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' : {
     # Variables for js2gtest rules
     'gypv8sh': '../tools/gypv8sh.py',
     'js2gtest': 'test/base/js2gtest.js',
     'mock_js': 'third_party/mock4js/mock4js.js',
     'test_api_js': 'test/data/webui/test_api.js',
@@ skipping 2470 matching lines @@
         'browser/chromeos/media/media_player_browsertest.cc',
         'browser/chromeos/notifications/notification_browsertest.cc',
         'browser/chromeos/panels/panel_browsertest.cc',
         'browser/chromeos/status/accessibility_menu_button_browsertest.cc',
         'browser/chromeos/status/caps_lock_menu_button_browsertest.cc',
         'browser/chromeos/status/clock_menu_button_browsertest.cc',
         'browser/chromeos/status/input_method_menu_button_browsertest.cc',
         'browser/chromeos/status/power_menu_button_browsertest.cc',
         'browser/chromeos/status/status_area_view_browsertest.cc',
         'browser/chromeos/setting_level_bubble_browsertest.cc',
+        'browser/chromeos/system_key_event_listener_browsertest.cc',
         'browser/chromeos/tab_closeable_state_watcher_browsertest.cc',
         'browser/chromeos/volume_bubble_browsertest.cc',
         'browser/content_settings/content_settings_browsertest.cc',
         'browser/crash_recovery_browsertest.cc',
         'browser/custom_handlers/protocol_handler_registry_browsertest.cc',
         'browser/download/download_browsertest.cc',
         'browser/download/download_extension_apitest.cc',
         'browser/download/download_test_observer.cc',
         'browser/download/save_page_browsertest.cc',
         'browser/errorpage_browsertest.cc',
@@ skipping 1813 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'
 }