[mutter] wayland-surface: Only call process_damage when we have any damage

[Adel Gadllah <agadllah src gnome org>]

commit dd4d6af1854f71aefcfcca6112288eedcbdf3301
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Sun Apr 27 16:12:02 2014 +0200

    wayland-surface: Only call process_damage when we have any damage
    
    This fixes a crash when a client commits a surface
    without attaching a buffer.

 src/wayland/meta-wayland-surface.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 483c0c7..3a8a077 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -311,7 +311,8 @@ commit_pending_state (MetaWaylandSurface      *surface,
         }
     }
 
-  surface_process_damage (surface, pending->damage);
+  if (!cairo_region_is_empty (pending->damage))
+    surface_process_damage (surface, pending->damage);
 
   if (pending->opaque_region)
     meta_surface_actor_set_opaque_region (surface->surface_actor, pending->opaque_region);