Hide AXPlatformNode on ChromeOS.

ui/base/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/buildflag_header.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//testing/test.gni")
 import("//ui/base/ui_features.gni")
@@ skipping 35 matching lines @@
   # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
   configs += [ "//build/config/compiler:no_size_t_to_int_warning" ]
 }
 
 buildflag_header("ui_features") {
   header = "ui_features.h"
   flags = [
     "ENABLE_HIDPI=$enable_hidpi",
     "USE_XKBCOMMON=$use_xkbcommon",
     "MAC_VIEWS_BROWSER=$mac_views_browser",
+    "HAS_NATIVE_ACCESSIBILITY=$has_native_accessibility",
   ]
 }
 
 component("base") {
   output_name = "ui_base"
 
   sources = [
     "accelerators/menu_label_accelerator_util_linux.cc",
     "accelerators/menu_label_accelerator_util_linux.h",
     "accelerators/platform_accelerator.h",
@@ skipping 919 matching lines @@
 if (is_mac) {
   mac_framework_bundle("ui_unittests_framework") {
     testonly = true
     deps = [
       "//ui/resources:ui_test_pak_bundle_data",
     ]
     info_plist = "test/framework-Info.plist"
     output_name = "ui_unittests Framework"
   }
 }