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

build/config/ui.gni

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This file contains UI-related build flags (see features.gni for Chrome
 # feature-related ones). These should theoretically be moved to the ui
 # directory.
 #
 # However, today we have many "bad" dependencies on some of these flags from,
 # e.g. base, so they need to be global to match the GYP configuration. Also,
@@ skipping 24 matching lines @@
       (is_mac || is_win || is_chromeos || use_aura) && !is_chromecast
 
   # Whether the entire browser uses toolkit-views on Mac instead of Cocoa.
   mac_views_browser = false
 
   # Whether we should use GTKv3 instead of GTKv2.
   use_gtk3 = false
 
   # 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 -----------------------------------------------
 #
 # These variables depend on other variables and can't be set externally.
 
 # Use GPU accelerated cross process image transport by default on linux builds
 # with the Aura window manager.
 ui_compositor_image_transport = use_aura && is_linux
 
 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 {
   use_cairo = false
   use_pango = false
 }
 
 # Whether to use atk, the Accessibility ToolKit library
 use_atk = is_desktop_linux && use_x11
 
 use_clipboard_aurax11 = is_linux && use_aura && use_x11
 
 enable_hidpi = is_mac || is_win || is_linux
 
 enable_topchrome_md = is_chromeos || is_win || is_linux