Make chrome/browser/chromeos/accessibility compile on Athena with use_ash=0

ui/chromeos/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.
 
 component("ui_chromeos") {
   sources = [
+    "accessibility_types.h",
     "network/network_icon.cc",
     "network/network_icon.h",
     "network/network_icon_animation.cc",
     "network/network_icon_animation.h",
     "network/network_icon_animation_observer.h",
     "network/network_info.cc",
     "network/network_info.h",
     "network/network_list.cc",
     "network/network_list.h",
     "network/network_list_delegate.h",
     "touch_exploration_controller.cc",
     "touch_exploration_controller.h",
     "user_activity_power_manager_notifier.cc",
     "user_activity_power_manager_notifier.h",
   ]
   deps = [
     "//base",
     "//chromeos:power_manager_proto",
     "//skia",
     "//ui/aura",
     "//ui/chromeos/resources",
     "//ui/chromeos/strings",
     "//ui/events",
     "//ui/events:gesture_detection",
     "//ui/views",
     "//ui/wm",
   ]
   defines = [ "UI_CHROMEOS_IMPLEMENTATION" ]
 }