[gtk+/gtk-3-0] Make gdk_x11_window_set_theme_variant do nothing for non-toplevels

[Matthias Clasen <matthiasc src gnome org>]

commit 9c1b238bf98b6354b011be9a62d5d175a41014a0
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Apr 3 17:40:37 2011 -0400

    Make gdk_x11_window_set_theme_variant do nothing for non-toplevels
    
    This avoids problems when calling this e.g. on offscreen windows.

 gdk/x11/gdkwindow-x11.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)
---
diff --git a/gdk/x11/gdkwindow-x11.c b/gdk/x11/gdkwindow-x11.c
index fcca9d8..767433d 100644
--- a/gdk/x11/gdkwindow-x11.c
+++ b/gdk/x11/gdkwindow-x11.c
@@ -3105,7 +3105,12 @@ void
 gdk_x11_window_set_theme_variant_gtk_only (GdkWindow *window,
                                            char      *variant)
 {
-  GdkDisplay *display = gdk_window_get_display (window);
+  GdkDisplay *display;
+
+  if (!WINDOW_IS_TOPLEVEL (window))
+    return;
+
+  display = gdk_window_get_display (window);
 
   if (variant != NULL)
     {