build: Allow glib to be disabled for non-ozone builds of chromium when using GN.

build/config/ui.gni

Index: build/config/ui.gni
diff --git a/build/config/ui.gni b/build/config/ui.gni
index f7070bbf46af9103f4c96ffe239ad423e521e748..a5c038265e2b933a48acaa909e8911d14de36712 100644
--- a/build/config/ui.gni
+++ b/build/config/ui.gni
@@ -42,6 +42,9 @@ declare_args() {
 
   # Optional system libraries.
   use_xkbcommon = false
+
+  # Whether we should use glib, a low level C utility library.
+  use_glib = is_linux && !use_ozone

[Dirk Pranke, 2015/11/05 22:19:21]

This change probably doesn't do what you expect it to do.

See crbug.com/542846.

Depending on what you want to have happen, you might need to do:

declare_args() {
  use_glib = ''
}

if (use_glib == '') {
  use_glib = is-linux && !use_ozne
}

In order for it to be set correctly if one sets use_ozone explicitly in args.gn.

[reveman, 2015/11/05 23:15:07]

ah, got it.

 }
 
 # Additional dependent variables -----------------------------------------------
@@ -57,10 +60,7 @@ use_default_render_theme = use_aura && !is_android
 # Indicates if the UI toolkit depends on X11.
 use_x11 = is_linux && !use_ozone
 
-# Whether we should use glib, a low level C utility library.
-use_glib = is_linux && !use_ozone
-
-if (is_linux && use_glib) {
+if (is_linux && !use_ozone) {

[Dirk Pranke, 2015/11/05 22:19:21]

I'm not sure I understand this change. Are you saying
that whether we should use cairo and pango only depends
on ozone, and not glib?

[reveman, 2015/11/05 23:15:07]

Yes, use_glib should not affect this. A non-ozone build will always need
cairo/pango right now afaict.

   use_cairo = true
   use_pango = true
 } else {