Rename is_chromeos in chrome/src.

components/metrics/BUILD.gn

Index: components/metrics/BUILD.gn
diff --git a/components/metrics/BUILD.gn b/components/metrics/BUILD.gn
index 58e88bff883ce90998ffd90c6d4864a4d232ea1a..8746723547809aeea8c7aad5c57737df63ec441c 100644
--- a/components/metrics/BUILD.gn
+++ b/components/metrics/BUILD.gn
@@ -2,6 +2,8 @@
 # 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")
+
 # GYP version: components/metrics.gypi:metrics
 source_set("metrics") {
   sources = [
@@ -70,7 +72,7 @@ source_set("metrics") {
     "//third_party/zlib",
   ]
 
-  if (is_chromeos) {
+  if (use_cros_fe) {
     deps += [ ":serialization" ]
   }