[mutter] MetaRegionIterator: avoid reading off end of rectangles array

[Owen Taylor <otaylor src gnome org>]

commit 3f9c375f1c06787eeeda5c4ddbfce16963c8f421
Author: Owen W. Taylor <otaylor fishsoup net>
Date:   Mon Dec 6 11:49:24 2010 -0500

    MetaRegionIterator: avoid reading off end of rectangles array
    
    Fix an off-by-one error in the check for "can we peek ahead to the next
    rectangle".
    
    https://bugzilla.gnome.org/show_bug.cgi?id=636491

 src/compositor/region-utils.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/compositor/region-utils.c b/src/compositor/region-utils.c
index 9cfc393..b4071ca 100644
--- a/src/compositor/region-utils.c
+++ b/src/compositor/region-utils.c
@@ -180,7 +180,7 @@ meta_region_iterator_next (MetaRegionIterator *iter)
   iter->rectangle = iter->next_rectangle;
   iter->line_start = iter->line_end;
 
-  if (iter->i < iter->n_rectangles)
+  if (iter->i + 1 < iter->n_rectangles)
     {
       cairo_region_get_rectangle (iter->region, iter->i + 1, &iter->next_rectangle);
       iter->line_end = iter->next_rectangle.y != iter->rectangle.y;