Rename is_chromeos in chrome/src.

build/config/linux/BUILD.gn

 # Copyright (c) 2013 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/linux/pkg_config.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 import("//tools/generate_library_loader/generate_library_loader.gni")
 
@@ skipping 12 matching lines @@
                              [
                                rebase_path("//build/linux/sysroot_ld_path.sh",
                                            root_build_dir),
                                sysroot,
                              ],
                              "value") ]
   }
 
   # Set here because OS_CHROMEOS cannot be autodetected in build_config.h like
   # OS_LINUX and the like.
-  if (is_chromeos) {
+  if (use_cros_fe) {
     defines = [ "OS_CHROMEOS" ]
   }
 }
 
 config("fontconfig") {
   libs = [ "fontconfig" ]
 }
 
 pkg_config("freetype2") {
   packages = [ "freetype2" ]
@@ skipping 76 matching lines @@
 
 config("xtst") {
   libs = [ "Xtst" ]
 }
 
 config("libresolv") {
   libs = [ "resolv" ]
 }
 
 # CrOS doesn't install GTK, gconf or any gnome packages.
-if (!is_chromeos) {
+if (!use_cros_fe) {
   # These packages should _only_ be expected when building for a target.
   # If these extra checks are not run, gconf is required when building host
   # tools for a CrOS build.
   if (current_toolchain == default_toolchain) {
     pkg_config("atk") {
       packages = [ "atk" ]
       atk_lib_dir = exec_script(pkg_config_script,
                                 [
                                   "--libdir",
                                   "atk",
@@ skipping 109 matching lines @@
 
   functions = gypi_values.libudev_functions
 }
 
 group("udev") {
   deps = [
     ":udev0_loader",
     ":udev1_loader",
   ]
 }