[mutter] clutter/stage-cogl: Remove unnecessary variable: fb_damage

[Marge Bot <marge-bot src gnome org>]

commit 456f80022aca1cd4d554b5a15c499daa1415a709
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Thu Dec 17 15:25:35 2020 +0800

    clutter/stage-cogl: Remove unnecessary variable: fb_damage
    
    We no longer have use for a different value to fb_clip_region, so
    fb_damage no longer needs to exist.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1554>

 clutter/clutter/cogl/clutter-stage-cogl.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)
---
diff --git a/clutter/clutter/cogl/clutter-stage-cogl.c b/clutter/clutter/cogl/clutter-stage-cogl.c
index 410421b569..ca0ead5e71 100644
--- a/clutter/clutter/cogl/clutter-stage-cogl.c
+++ b/clutter/clutter/cogl/clutter-stage-cogl.c
@@ -548,25 +548,17 @@ clutter_stage_cogl_redraw_view_primary (ClutterStageCogl *stage_cogl,
 
       if (use_clipped_redraw)
         {
-          cairo_region_t *fb_damage;
           int age;
 
-          fb_damage = cairo_region_create ();
-
           for (age = 1; age <= buffer_age; age++)
             {
               const cairo_region_t *old_damage;
 
               old_damage =
                 clutter_damage_history_lookup (view_priv->damage_history, age);
-              cairo_region_union (fb_damage, old_damage);
+              cairo_region_union (fb_clip_region, old_damage);
             }
 
-          /* Update the fb clip region with the extra damage. */
-          cairo_region_union (fb_clip_region, fb_damage);
-
-          cairo_region_destroy (fb_damage);
-
           CLUTTER_NOTE (CLIPPING, "Reusing back buffer(age=%d) - repairing region: num rects: %d\n",
                         buffer_age,
                         cairo_region_num_rectangles (fb_clip_region));