[mutter] background: don't tank if background is destroyed before it gets a pipeline

[Ray Strode <halfline src gnome org>]

commit 577e5e2e1abf77e000cf870c72aaeace35b84bd4
Author: Ray Strode <rstrode redhat com>
Date:   Mon Mar 25 17:24:01 2013 -0400

    background: don't tank if background is destroyed before it gets a pipeline
    
    Right now we call unset_texture from MetaBackground's dispose method.
    
    unset_texture assumes there's a pipeline available, but there may not
    be if the object was just created.
    
    This commit fixes that incorrect assumption.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=696157

 src/compositor/meta-background.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/meta-background.c b/src/compositor/meta-background.c
index 3380957..d15b06c 100644
--- a/src/compositor/meta-background.c
+++ b/src/compositor/meta-background.c
@@ -704,7 +704,8 @@ static void
 unset_texture (MetaBackground *self)
 {
   MetaBackgroundPrivate *priv = self->priv;
-  cogl_pipeline_set_layer_texture (priv->pipeline, 0, NULL);
+  if (priv->pipeline != NULL)
+    cogl_pipeline_set_layer_texture (priv->pipeline, 0, NULL);
 
   g_clear_pointer (&priv->texture,
                    (GDestroyNotify)