Rename is_chromeos in chrome/src.

extensions/shell/common/api/schemas.gni

Index: extensions/shell/common/api/schemas.gni
diff --git a/extensions/shell/common/api/schemas.gni b/extensions/shell/common/api/schemas.gni
index 3f14cfc0097d8241981a05ee7836cecfefa6fc29..129cac015f883365ccfdf35520b88d6ea452f2a7 100644
--- a/extensions/shell/common/api/schemas.gni
+++ b/extensions/shell/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
 }