aura: Explicitly disable GTK

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index f5b5bc1bf0d2cce1a4ce5692f097b7d4059e7b0b..ada70b2b9145bc18a628d2e9636b8cc9a0f0da6f 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -231,15 +231,22 @@
 
         # Flags to use Gtk and X11 on non-Mac POSIX platforms
         ['OS=="win" or OS=="mac"', {
+          'toolkit_uses_glib%': 0,
           'toolkit_uses_gtk%': 0,
           'use_x11%': 0,
         }, {
           # TODO(dnicoara) Wayland build should have these disabled, but
           # currently GTK and X is too spread and it's hard to completely
           # remove every dependency.
+          'toolkit_uses_glib%': 1,
           'toolkit_uses_gtk%': 1,
           'use_x11%': 1,
         }],
+        ['use_aura==1', {
+          'toolkit_uses_glib%': 1,
+          'toolkit_uses_gtk%': 0,
+          'use_x11%': 1,
+        }],
 
         # A flag to enable or disable our compile-time dependency
         # on gnome-keyring. If that dependency is disabled, no gnome-keyring
@@ -297,6 +304,7 @@
     'views_compositor%': '<(views_compositor)',
     'use_aura%': '<(use_aura)',
     'os_posix%': '<(os_posix)',
+    'toolkit_uses_glib%': '<(toolkit_uses_glib)',
     'toolkit_uses_gtk%': '<(toolkit_uses_gtk)',
     'use_skia%': '<(use_skia)',
     'use_x11%': '<(use_x11)',