Rename is_chromeos in chrome/src.

build/config/features.gni

Index: build/config/features.gni
diff --git a/build/config/features.gni b/build/config/features.gni
index b1e9280c0921a5e4d1057ed114f07f16961abc40..31cc4a9ec2553ad1b0fbff374cc119188c22f484 100644
--- a/build/config/features.gni
+++ b/build/config/features.gni
@@ -25,6 +25,11 @@ declare_args() {
 
   enable_plugins = !is_android && !is_ios
 
+  # This indicates whether the chromeos interfaces and features should be
+  # made available.  Contrast with whether we are targetting the embedded
+  # OS.  That flag controls the linking, flags, filesystems, etc. we expect.
+  use_cros_fe = is_chromeos
+
   # Enables Native Client support.
   # TODO(GYP): Get NaCl linking on other platforms.
   # Also, see if we can always get rid of enable_nacl_untrusted and
@@ -36,7 +41,7 @@ declare_args() {
   # the commented out logic.
   # Eventually we want this to be:
   #   enable_nacl = !is_ios && !is_android
-  enable_nacl = (is_linux && !is_chromeos && current_cpu == "x64") || is_nacl
+  enable_nacl = (is_linux && !use_cros_fe && current_cpu == "x64") || is_nacl
   enable_nacl_untrusted = enable_nacl
   enable_pnacl = enable_nacl_untrusted
 
@@ -82,7 +87,7 @@ declare_args() {
 
   enable_google_now = !is_ios && !is_android
 
-  enable_one_click_signin = is_win || is_mac || (is_linux && !is_chromeos)
+  enable_one_click_signin = is_win || is_mac || (is_linux && !use_cros_fe)
 
   enable_remoting = !is_ios && !is_android
 
@@ -143,7 +148,7 @@ enable_spellcheck = !is_ios
 use_browser_spellchecker = is_android || is_mac
 
 # Enable basic printing support and UI.
-enable_basic_printing = !is_chromeos
+enable_basic_printing = !use_cros_fe
 
 # Enable printing with print preview. It does not imply
 # enable_basic_printing. It's possible to build Chrome with preview only.
@@ -180,32 +185,47 @@ win_pdf_metafile_for_printing = true
 
 # Whether we are using the rlz library or not.  Platforms like Android send
 # rlz codes for searches but do not use the library.
-enable_rlz_support = is_win || is_mac || is_ios || is_chromeos
+enable_rlz_support = is_win || is_mac || is_ios || use_cros_fe
 enable_rlz = is_chrome_branded && enable_rlz_support
 
-enable_settings_app = enable_app_list && !is_chromeos
+enable_settings_app = enable_app_list && !use_cros_fe
 
 enable_service_discovery = enable_mdns || is_mac
 
 enable_wifi_bootstrapping = is_win || is_mac
 
 # Image loader extension is enabled on ChromeOS only.
-enable_image_loader_extension = is_chromeos
+enable_image_loader_extension = use_cros_fe
 
 # Chrome OS: whether to also build the upcoming version of
 # ChromeVox, which can then be enabled via a command-line switch.
 enable_chromevox_next = false
 
 # Use brlapi from brltty for braille display support.
-use_brlapi = is_chromeos
+use_brlapi = use_cros_fe
 
 # Option controlling the use of GConf (the classic GNOME configuration
 # system).
 # TODO(GYP) also require !embedded to enable.
-use_gconf = is_linux && !is_chromeos
+use_gconf = is_linux && !use_cros_fe
 
 # Whether to back up data before sync.
-enable_pre_sync_backup = is_win || is_mac || (is_linux && !is_chromeos)
+enable_pre_sync_backup = is_win || is_mac || (is_linux && !use_cros_fe)
 
 # WebVR support disabled until platform implementations have been added
 enable_webvr = false
+
+#
+#  Maintain some sanity for refactoring build configs.
+#
+if (is_chromeos_os) {
+  assert(use_cros_fe, "ChromeOS targetting requires ChromeOS UI")
+}
+
+if (use_cros_fe) {
+  assert(!is_desktop_linux, "ChromeOS Frontend is not desktop linux")
+}
+
+assert(use_cros_fe == is_chromeos,
+       "is_chromeos and use_cros_fe are expected to be aliases, " +
+           "old and new, respectively")