Introduce GN to desktop_linux arg and grit_defines list.

build/config/ui.gni

Index: build/config/ui.gni
diff --git a/build/config/ui.gni b/build/config/ui.gni
index 360e860ef8fbf5831efe5a588ea77646ae1928b9..dea686f1aea23a0cf27bdabdabc33be064e90178 100644
--- a/build/config/ui.gni
+++ b/build/config/ui.gni
@@ -12,6 +12,8 @@
 # See also build/config/features.gni
 
 declare_args() {
+  desktop_linux = is_linux && !is_chromeos

[brettw, 2014/05/27 23:54:23]

Since it seems like we're stuck with this, can you put this in
build/common/BUILDCONFIG.gn where the other is_linux, etc are defined, and call
it is_desktop_linux?

[tfarina, 2014/05/30 03:02:07]

Done.

+
   # Indicates if Ash is enabled. Ash is the Aura Shell which provides a
   # desktop-like environment for Aura. Requires use_aura = true
   use_ash = is_win || is_chromeos
@@ -56,3 +58,12 @@ use_x11 = is_linux && !use_ozone
 use_glib = is_linux
 
 use_clipboard_aurax11 = is_linux && use_aura && use_x11
+
+grit_defines = []

[tfarina, 2014/05/23 19:38:37]

in GYP this is declared in build/common.gypi.

Where in GN would be a better place for this?

[brettw, 2014/05/27 23:51:03]

I think you can just put this in the grit_rule.gni file itself, unless it needs
to be used outside of that file.

[tfarina, 2014/05/30 03:02:07]

Done.

+if (is_chromeos) {
+  grit_defines += [ "-D", "chromeos", "-D", "scale_factors=2x"]
+}
+
+if (desktop_linux) {
+  grit_defines += [ "-D", "desktop_linux" ]
+}