[metacity] xrender: do not recreate extents in window_opacity_changed

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 6fcc0d6b73c2d40b6054d4334d47ce5002c66c4e
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Sat Sep 21 22:48:53 2019 +0300

    xrender: do not recreate extents in window_opacity_changed
    
    Window extents are not affected by opacity. Just add damage region
    to redraw window with new opacity.

 src/compositor/meta-compositor-xrender.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)
---
diff --git a/src/compositor/meta-compositor-xrender.c b/src/compositor/meta-compositor-xrender.c
index 2b232997..7a7fe49d 100644
--- a/src/compositor/meta-compositor-xrender.c
+++ b/src/compositor/meta-compositor-xrender.c
@@ -2591,12 +2591,11 @@ meta_compositor_xrender_window_opacity_changed (MetaCompositor *compositor,
     }
 
   if (cw->extents)
-    XFixesDestroyRegion (xrender->xdisplay, cw->extents);
-  cw->extents = win_extents (xrender, cw);
-
-  cw->damaged = TRUE;
-
-  add_repair (xrender);
+    {
+      meta_compositor_add_damage (compositor,
+                                  "window_opacity_changed",
+                                  cw->extents);
+    }
 }
 
 static void