[mutter] theme: Make sure to clear the entirety of buttons properly

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

commit 12771a555a9954ba9f002b7e422385cf2e904e86
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Jun 23 15:23:45 2015 -0700

    theme: Make sure to clear the entirety of buttons properly
    
    In commit cc5def1, buttons were changed from GdkRectangles to
    MetaButtonSpace units, but the corresponding memset hack was not.
    
    This means that the clickable portion of the unshade rectangle
    was always set to uninitalized memory. The effects of this were
    random, but in cases where the moon is aligned just right, the
    rectangle would graze over the borders, and so it would take priority
    over other borders and show a pointer cursor instead of a resize
    cursor.

 src/ui/theme-private.h |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/ui/theme-private.h b/src/ui/theme-private.h
index cdf23a0..a61457e 100644
--- a/src/ui/theme-private.h
+++ b/src/ui/theme-private.h
@@ -115,7 +115,7 @@ struct _MetaFrameGeometry
 
   /* used for a memset hack */
 #define ADDRESS_OF_BUTTON_RECTS(fgeom) (((char*)(fgeom)) + G_STRUCT_OFFSET (MetaFrameGeometry, close_rect))
-#define LENGTH_OF_BUTTON_RECTS (G_STRUCT_OFFSET (MetaFrameGeometry, unstick_rect) + sizeof (GdkRectangle) - 
G_STRUCT_OFFSET (MetaFrameGeometry, close_rect))
+#define LENGTH_OF_BUTTON_RECTS (G_STRUCT_OFFSET (MetaFrameGeometry, unstick_rect) + sizeof (MetaButtonSpace) 
- G_STRUCT_OFFSET (MetaFrameGeometry, close_rect))
 
   /* The button rects (if changed adjust memset hack) */
   MetaButtonSpace close_rect;