Rename is_chromeos in chrome/src.

chrome/browser/extensions/BUILD.gn

Index: chrome/browser/extensions/BUILD.gn
diff --git a/chrome/browser/extensions/BUILD.gn b/chrome/browser/extensions/BUILD.gn
index 0acb058e12b5f758038ad3fbf771e12255254ddb..5f4631bff66d673ad75bea277c3fdf617456caac 100644
--- a/chrome/browser/extensions/BUILD.gn
+++ b/chrome/browser/extensions/BUILD.gn
@@ -85,7 +85,7 @@ source_set("extensions") {
     "//storage/browser",
   ]
 
-  if (is_chromeos) {
+  if (use_cros_fe) {
     sources +=
         rebase_path(gypi_values.chrome_browser_extensions_chromeos_sources,
                     ".",
@@ -169,7 +169,7 @@ source_set("extensions") {
   }
 
   # chromeos uses its own global_shortcut_listener, _x11 is not necessary.
-  if (is_chromeos || !use_x11) {
+  if (use_cros_fe || !use_x11) {
     sources -= [
       "global_shortcut_listener_x11.cc",
       "global_shortcut_listener_x11.h",
@@ -189,7 +189,7 @@ source_set("extensions") {
       "//third_party/iaccessible2",
       "//third_party/isimpledom",
     ]
-  } else if (use_aura && !is_chromeos) {
+  } else if (use_aura && !use_cros_fe) {
     sources += [
       "display_info_provider_aura.cc",
       "display_info_provider_aura.h",
@@ -203,7 +203,7 @@ source_set("extensions") {
                     "//chrome")
   }
 
-  if (is_chromeos && use_ozone) {
+  if (use_cros_fe && use_ozone) {
     sources -= [ "global_shortcut_listener_chromeos.cc" ]
   }
   if (!use_ozone) {