[gnome-shell] st: Fix crash in theme-node-transition

[Florian MÃllner <fmuellner src gnome org>]

commit 8bd5b1e696e47ceedfb77f48128b2cc16c73c922
Author: Florian MÃllner <fmuellner gnome org>
Date:   Wed Sep 21 22:37:06 2011 +0200

    st: Fix crash in theme-node-transition
    
    Setting up the framebuffers for transitions may fail, in which case
    the material used for drawing is left uninitialized, so trying to
    access it results in a crash.
    Instead bail out in this case, which means that we won't paint
    anything during the transition - still, drawing errors are better
    than crashes ...
    
    https://bugzilla.gnome.org/show_bug.cgi?id=659676

 src/st/st-theme-node-transition.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/st/st-theme-node-transition.c b/src/st/st-theme-node-transition.c
index 3da45ae..7bb83cd 100644
--- a/src/st/st-theme-node-transition.c
+++ b/src/st/st-theme-node-transition.c
@@ -328,6 +328,9 @@ st_theme_node_transition_paint (StThemeNodeTransition *transition,
 
       calculate_offscreen_box (transition, allocation);
       priv->needs_setup = !setup_framebuffers (transition, allocation);
+
+      if (priv->needs_setup) /* setting up framebuffers failed */
+        return;
     }
 
   cogl_color_set_from_4f (&constant, 0., 0., 0.,