gdkwindow-x11: always set _GTK_THEME_VARIANT property

Set _GTK_THEME_VARIANT to empty string when default theme variant
is used. This will allow to understand whether _GTK_THEME_VARIANT
is not supported or default variant is requested.

https://bugzilla.gnome.org/show_bug.cgi?id=761476

diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index ffe97767f051661480979ca214b989c7203092a2..8544de87f5f49ae489a068110ce9015a8c7ac1d2 100644 (file)
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -3728,7 +3728,8 @@ void
 gdk_x11_window_set_theme_variant (GdkWindow *window,
                                   char      *variant)
 {
-  gdk_x11_window_set_utf8_property (window, "_GTK_THEME_VARIANT", variant);
+  gdk_x11_window_set_utf8_property (window, "_GTK_THEME_VARIANT",
+                                    variant ? variant : "");
 }
 
 #define GDK_SELECTION_MAX_SIZE(display)                                 \