Rename & rework is_chromeos

build/config/BUILDCONFIG.gn

Index: build/config/BUILDCONFIG.gn
diff --git a/build/config/BUILDCONFIG.gn b/build/config/BUILDCONFIG.gn
index 706a439aa00c2f3e7e27a080a44af432341dbc4e..1c3fb30d21ef05999a9d76778a203b20c44ee04e 100644
--- a/build/config/BUILDCONFIG.gn
+++ b/build/config/BUILDCONFIG.gn
@@ -82,12 +82,16 @@ declare_args() {
   # Compile for Thread Sanitizer to find threading bugs.
   is_tsan = false
 
-  if (current_os == "chromeos") {
-    # Allows the target toolchain to be injected as arguments. This is needed
-    # to support the CrOS build system which supports per-build-configuration
-    # toolchains.
-    cros_use_custom_toolchain = false
-  }
+  # Used for compiling chromeos interface on linux OSes.
+  is_chromeos_ui = current_os == "chromeos"
+
+  # This controls some aspects fo being a traditional desktop linux
+  is_desktop_linux = current_os == "linux" && !is_chromeos_ui
+
+  # Allows the target toolchain to be injected as arguments. This is needed
+  # to support the CrOS build system which supports per-build-configuration
+  # toolchains.
+  cros_use_custom_toolchain = false
 }
 
 # =============================================================================
@@ -97,12 +101,15 @@ declare_args() {
 # We set these various is_FOO booleans for convenience in writing OS-based
 # conditions.
 #
-# - is_android, is_chromeos, is_ios, and is_win should be obvious.
+# - is_android, is_ios, and is_win should be obvious.
 # - is_mac is set only for desktop Mac. It is not set on iOS.
 # - is_posix is true for mac and any Unix-like system (basically everything
 #   except Windows).
 # - is_linux is true for desktop Linux and ChromeOS, but not Android (which is
 #   generally too different despite being based on the Linux kernel).
+# - is_chromeos_os is true when compiling for a destination chromeos device.
+# - is_chromeos_ui is true when compiling for either a chromeos device or
+#   debugging on desktop for the same.
 #
 # Do not add more is_* variants here for random lesser-used Unix systems like
 # aix or one of the BSDs. If you need to check these, just check the os value
@@ -110,7 +117,7 @@ declare_args() {
 
 if (current_os == "win") {
   is_android = false
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = false
   is_linux = false
   is_mac = false
@@ -119,7 +126,7 @@ if (current_os == "win") {
   is_win = true
 } else if (current_os == "mac") {
   is_android = false
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = false
   is_linux = false
   is_mac = true
@@ -128,7 +135,7 @@ if (current_os == "win") {
   is_win = false
 } else if (current_os == "android") {
   is_android = true
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = false
   is_linux = false
   is_mac = false
@@ -137,7 +144,8 @@ if (current_os == "win") {
   is_win = false
 } else if (current_os == "chromeos") {
   is_android = false
-  is_chromeos = true
+  is_chromeos_ui = true
+  is_chromeos_os = true
   is_ios = false
   is_linux = true
   is_mac = false
@@ -148,7 +156,7 @@ if (current_os == "win") {
   # current_os == "nacl" will be passed by the nacl toolchain definition. It is not
   # set by default or on the command line. We treat is as a Posix variant.
   is_android = false
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = false
   is_linux = false
   is_mac = false
@@ -157,7 +165,7 @@ if (current_os == "win") {
   is_win = false
 } else if (current_os == "ios") {
   is_android = false
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = true
   is_linux = false
   is_mac = false
@@ -166,7 +174,7 @@ if (current_os == "win") {
   is_win = false
 } else if (current_os == "linux") {
   is_android = false
-  is_chromeos = false
+  is_chromeos_os = false
   is_ios = false
   is_linux = true
   is_mac = false
@@ -175,7 +183,6 @@ if (current_os == "win") {
   is_win = false
 }
 
-is_desktop_linux = is_linux && !is_chromeos
 
 # =============================================================================
 # CPU ARCHITECTURE
@@ -276,7 +283,7 @@ if (!is_android) {
     "*\bandroid/*",
   ]
 }
-if (!is_chromeos) {
+if (!is_chromeos_ui) {
   sources_assignment_filter += [
     "*_chromeos.h",
     "*_chromeos.cc",