[mutter] window: Fix meta_window_get_workspaces when a window isn't on a workspace

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

commit 578b1c06c7c3ee63c59a2e98e84579c168686d7c
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Mar 13 00:37:31 2012 -0400

    window: Fix meta_window_get_workspaces when a window isn't on a workspace
    
    Since we're going to be evaluating the work area at startup now, we need
    to make sure that we don't iterate over workspaces before they're assigned.
    The easiest way to do this is to make sure that meta_window_get_workspaces
    doesn't crash.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=643606

 src/core/window.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/core/window.c b/src/core/window.c
index ff09914..c237c0d 100644
--- a/src/core/window.c
+++ b/src/core/window.c
@@ -7475,8 +7475,10 @@ meta_window_get_workspaces (MetaWindow *window)
 {
   if (window->on_all_workspaces)
     return window->screen->workspaces;
-  else
+  else if (window->workspace != NULL)
     return window->workspace->list_containing_self;
+  else
+    return NULL;
 }
 
 static void