[gnome-shell] st-widget: Don't add hidden actors to the paint volume

[Adel Gadllah <agadllah src gnome org>]

commit ea55c36a3a2f1abcaa8e202e0f67a29ed807cebe
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Fri Mar 1 18:52:02 2013 +0100

    st-widget: Don't add hidden actors to the paint volume
    
    We are not painting them anyway.

 src/st/st-widget.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/st/st-widget.c b/src/st/st-widget.c
index 65de272..42992ec 100644
--- a/src/st/st-widget.c
+++ b/src/st/st-widget.c
@@ -791,6 +791,9 @@ st_widget_get_paint_volume (ClutterActor *self,
         {
           const ClutterPaintVolume *child_volume;
 
+          if (!CLUTTER_ACTOR_IS_VISIBLE (child))
+            continue;
+
           child_volume = clutter_actor_get_transformed_paint_volume (child, self);
           if (!child_volume)
             return FALSE;