Rename is_chromeos in chrome/src.

extensions/browser/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/crypto.gni")
 import("//build/config/features.gni")
 import("//extensions/extensions.gni")
 
 # GYP version: extensions/extensions.gyp:extensions_browser
 source_set("browser") {
@@ skipping 46 matching lines @@
       "//components/variations",
       "//crypto:platform",
       "//device/bluetooth",
       "//device/core",
       "//device/hid",
       "//device/serial",
       "//device/usb",
       "//extensions/common/api/cast_channel:cast_channel_proto",
     ]
 
-    if (is_chromeos) {
+    if (use_cros_fe) {
       deps += [ "//chromeos" ]
     }
 
-    if (is_chromeos) {
+    if (use_cros_fe) {
       chromeos_sources = rebase_path(
               extensions_gypi_values.extensions_browser_sources_chromeos,
               ".",
               "//extensions")
       sources += chromeos_sources
     } else {
       nonchromeos_sources = rebase_path(
               extensions_gypi_values.extensions_browser_sources_nonchromeos,
               ".",
               "//extensions")
@@ skipping 14 matching lines @@
           win_or_mac_sources = rebase_path(
                   extensions_gypi_values.extensions_browser_sources_win_or_mac,
                   ".",
                   "//extensions")
           sources += win_or_mac_sources
         }
       }
     }
   }
 }