[gtk+] Optimize gdk_window_set_shape_combine_region

[Matthias Clasen <matthiasc src gnome org>]

commit 208d717fefb7d1d1faa0dada132a290036b458d0
Author: Matthias Clasen <mclasen redhat com>
Date:   Tue Dec 14 22:21:39 2010 -0500

    Optimize gdk_window_set_shape_combine_region
    
    When setting no shape on an unshaped window, nothing changes,
    so return early instead of recomputing lots of visibility
    information.
    
    Pointed out by Owen Taylor in bug 637156.

 gdk/gdkwindow.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index becfba5..54f5d2f 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -7167,6 +7167,9 @@ gdk_window_shape_combine_region (GdkWindow       *window,
   if (GDK_WINDOW_DESTROYED (window))
     return;
 
+  if (!window->shape && shape_region == NULL)
+    return;
+
   window->shaped = (shape_region != NULL);
 
   if (window->shape)