[mutter/gnome-3-36] clutter/stage-cogl: Avoid copying fb_clip_region

[Robert Mader <rmader src gnome org>]

commit 9919c8c3e6d33d3fb94ebecf15cdf7a6a4935caf
Author: Daniel van Vugt <daniel van vugt canonical com>
Date:   Wed Nov 18 19:08:38 2020 +0800

    clutter/stage-cogl: Avoid copying fb_clip_region
    
    Because it gets destroyed (unreferenced) immediately after that.
    This avoids a deep copy of potentially kilobytes of data.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1572>
    
    (cherry picked from commit 32b68478ede34caee447c9803addedc12a4df6c7)

 clutter/clutter/cogl/clutter-stage-cogl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/clutter/clutter/cogl/clutter-stage-cogl.c b/clutter/clutter/cogl/clutter-stage-cogl.c
index 9031f52915..0d99ba4bc5 100644
--- a/clutter/clutter/cogl/clutter-stage-cogl.c
+++ b/clutter/clutter/cogl/clutter-stage-cogl.c
@@ -935,7 +935,7 @@ clutter_stage_cogl_redraw_view (ClutterStageWindow *stage_window,
         }
       else
         {
-          swap_region = cairo_region_copy (fb_clip_region);
+          swap_region = cairo_region_reference (fb_clip_region);
           do_swap_buffer = TRUE;
         }
     }