Rename is_chromeos in chrome/src.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 80b13e6701dea860bb18cb0ee9a3dd1a907b7692..287e11a719ff12152021195732187cf1f255218a 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -178,7 +178,7 @@ config("compiler") {
     # Stack protection.
     if (is_mac) {
       cflags += [ "-fstack-protector-all" ]
-    } else if (is_posix && !is_chromeos && !is_nacl) {
+    } else if (is_posix && !is_chromeos_ui && !is_nacl) {
       # TODO(phajdan.jr): Use -fstack-protector-strong when our gcc supports it.
       cflags += [ "--param=ssp-buffer-size=4" ]
       if (is_android && (current_cpu == "arm64" || current_cpu == "x86")) {
@@ -189,7 +189,7 @@ config("compiler") {
     }
 
     # Linker warnings.
-    if (!(is_chromeos && current_cpu == "arm") && !is_mac && !is_ios) {
+    if (!(is_chromeos_os && current_cpu == "arm") && !is_mac && !is_ios) {
       # TODO(jochen): Enable this on chromeos on arm. http://crbug.com/356580
       ldflags += [ "-Wl,--fatal-warnings" ]
     }
@@ -498,7 +498,7 @@ config("compiler") {
     }
 
     # TODO(thestig): Make this flag work with GN.
-    #if (!is_official_build && !is_chromeos && !(is_asan || is_lsan || is_tsan || is_msan)) {
+    #if (!is_official_build && !is_chromeos_os && !(is_asan || is_lsan || is_tsan || is_msan)) {
     #  ldflags += [
     #    "-Wl,--detect-odr-violations",
     #  ]
@@ -1136,7 +1136,7 @@ config("no_incompatible_pointer_warnings") {
     cflags += [ "-Wno-incompatible-pointer-types" ]
   } else if (current_cpu == "mipsel") {
     cflags += [ "-w" ]
-  } else if (is_chromeos && current_cpu == "arm") {
+  } else if (is_chromeos_os && current_cpu == "arm") {
     cflags += [ "-w" ]
   }
 }