Add MetalayerToolTest

ash/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
 
 # Historical note: Ash shipped on Windows for a couple years to support
@@ skipping 1178 matching lines @@
     "system/ime/tray_ime_chromeos_unittest.cc",
     "system/ime_menu/ime_menu_tray_unittest.cc",
     "system/media_security/multi_profile_media_tray_item_unittest.cc",
     "system/network/sms_observer_unittest.cc",
     "system/network/vpn_list_unittest.cc",
     "system/overview/overview_button_tray_unittest.cc",
     "system/palette/mock_palette_tool_delegate.cc",
     "system/palette/mock_palette_tool_delegate.h",
     "system/palette/palette_tool_manager_unittest.cc",
     "system/palette/tools/create_note_unittest.cc",
+    "system/palette/tools/metalayer_unittest.cc",
     "system/palette/tools/screenshot_unittest.cc",
     "system/power/power_event_observer_unittest.cc",
     "system/power/power_status_unittest.cc",
     "system/power/power_status_view_unittest.cc",
     "system/power/tablet_power_button_controller_unittest.cc",
     "system/power/tray_power_unittest.cc",
     "system/power/video_activity_notifier_unittest.cc",
     "system/screen_security/screen_tray_item_unittest.cc",
     "system/session/logout_confirmation_controller_unittest.cc",
     "system/session/tray_session_length_limit_unittest.cc",
@@ skipping 284 matching lines @@
     "//content/public/app:both",
     "//device/bluetooth",
   ]
 
   data_deps = [
     "//ash/strings:ash_test_strings",
     "//ash/resources:ash_test_resources_with_content_100_percent",
     "//ash/resources:ash_test_resources_200_percent",
   ]
 }