Rename is_chromeos in chrome/src.

ui/display/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/ui.gni")
 import("//testing/test.gni")
 
-if (is_chromeos) {
+if (use_cros_fe) {
   component("display") {
     sources = [
       "chromeos/apply_content_protection_task.cc",
       "chromeos/apply_content_protection_task.h",
       "chromeos/configure_displays_task.cc",
       "chromeos/configure_displays_task.h",
       "chromeos/display_configurator.cc",
       "chromeos/display_configurator.h",
       "chromeos/display_layout_manager.h",
       "chromeos/display_util.cc",
@@ skipping 133 matching lines @@
   ]
 
   deps = [
     "//base",
     "//base/test:run_all_unittests",
     "//testing/gtest",
     "//ui/display/util",
     "//ui/gfx/geometry",
   ]
 
-  if (is_chromeos) {
+  if (use_cros_fe) {
     deps += [
       ":display",
       ":test_support",
       ":test_util",
       "//base/test:test_support",
       "//ui/display/types",
     ]
   }
 
-  if (use_ozone && is_chromeos) {
+  if (use_ozone && use_cros_fe) {
     sources -= [
       "chromeos/x11/display_util_x11_unittest.cc",
       "chromeos/x11/native_display_event_dispatcher_x11_unittest.cc",
     ]
   }
 }