[mutter] window-actor: Fix optimization in get_paint_volume

[Jasper St. Pierre <jstpierre src gnome org>]

commit 8e74880b5562014d591398c3bc53a7961adb1965
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Fri Dec 6 11:44:42 2013 -0500

    window-actor: Fix optimization in get_paint_volume
    
    We need to clip the paint volume to the unobscured region, not the
    other way around...
    
    https://bugzilla.gnome.org/show_bug.cgi?id=720630

 src/compositor/meta-window-actor.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/meta-window-actor.c b/src/compositor/meta-window-actor.c
index 8344d10..a2c05ca 100644
--- a/src/compositor/meta-window-actor.c
+++ b/src/compositor/meta-window-actor.c
@@ -695,7 +695,11 @@ meta_window_actor_get_paint_volume (ClutterActor       *actor,
     }
 
   if (priv->unobscured_region)
-    cairo_region_intersect_rectangle (priv->unobscured_region, &bounds);
+    {
+      cairo_rectangle_int_t unobscured_bounds;
+      cairo_region_get_extents (priv->unobscured_region, &unobscured_bounds);
+      gdk_rectangle_intersect (&bounds, &unobscured_bounds, &bounds);
+    }
 
   origin.x = bounds.x;
   origin.y = bounds.y;