Adds TraySessionLengthLimitTest to ash_unittests.

ash/ash.gyp

 # 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': {
     'chromium_code': 1,
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
   },
   'includes': [
@@ skipping 801 matching lines @@
         'shell/window_watcher_unittest.cc',
         'shell_unittest.cc',
         'system/chromeos/managed/tray_locally_managed_user_unittest.cc',
         'system/chromeos/network/network_state_notifier_unittest.cc',
         'system/chromeos/power/power_event_observer_unittest.cc',
         'system/chromeos/power/power_status_unittest.cc',
         'system/chromeos/power/tray_power_unittest.cc',
         'system/chromeos/screen_security/screen_tray_item_unittest.cc',
         'system/chromeos/tray_display_unittest.cc',
         'system/date/date_view_unittest.cc',
+        'system/session_length_limit/tray_session_length_limit_unittest.cc',
         'system/tray/system_tray_unittest.cc',
         'system/tray/tray_details_view_unittest.cc',
         'system/user/tray_user_unittest.cc',
         'system/web_notification/web_notification_tray_unittest.cc',
         'test/ash_test_helper_unittest.cc',
         'test/ash_unittests.cc',
         'tooltips/tooltip_controller_unittest.cc',
         'touch/touch_observer_hud_unittest.cc',
         'wm/app_list_controller_unittest.cc',
         'wm/ash_native_cursor_manager_unittest.cc',
@@ skipping 163 matching lines @@
             },
           },
           'dependencies': [
             '../sandbox/sandbox.gyp:sandbox',
           ],
         }],
       ],
     },
   ],
 }