[libwnck] tasklist: Fix tasklist taking some space when there is no window

[Vincent Untz <vuntz src gnome org>]

commit efe6a2cc1ce834fd0bd8d40953b328c86e178828
Author: Vincent Untz <vuntz gnome org>
Date:   Fri Jul 22 14:56:12 2011 +0200

    tasklist: Fix tasklist taking some space when there is no window
    
    We were adding a non-empty size hint even when there is no window.

 libwnck/tasklist.c |    7 +++++++
 1 files changed, 7 insertions(+), 0 deletions(-)
---
diff --git a/libwnck/tasklist.c b/libwnck/tasklist.c
index 7e74d47..e44a192 100644
--- a/libwnck/tasklist.c
+++ b/libwnck/tasklist.c
@@ -1008,6 +1008,13 @@ wnck_tasklist_layout (GtkAllocation *allocation,
 {
   int n_cols, n_rows;
 
+  if (n_buttons == 0)
+    {
+      *n_cols_out = 0;
+      *n_rows_out = 0;
+      return 0;
+    }
+
   /* How many rows fit in the allocation */
   n_rows = allocation->height / max_height;