Rename is_chromeos in chrome/src.

extensions/common/api/schemas.gni

Index: extensions/common/api/schemas.gni
diff --git a/extensions/common/api/schemas.gni b/extensions/common/api/schemas.gni
index d584aa6b37b5baaa1738b6fc12438ee0a2d3105b..46aca48c6e99abf8048cb4ca25007ddf2c120716 100644
--- a/extensions/common/api/schemas.gni
+++ b/extensions/common/api/schemas.gni
@@ -2,13 +2,15 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//build/config/features.gni")
+
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("schemas.gypi") ],
                           "scope",
                           [ "schemas.gypi" ])
 
 sources = gypi_values.schema_files
-if (is_chromeos) {
+if (use_cros_fe) {
   sources += gypi_values.chromeos_schema_files
 }