[metacity] compositor: fix frame drawing with opacity

[Alberts Muktupāvels <muktupavels src gnome org>]

commit 6e7c51c239471a2213cde617daf41899f1d25d65
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Mon Mar 6 16:42:10 2017 +0200

    compositor: fix frame drawing with opacity

 src/compositor/meta-compositor-xrender.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/compositor/meta-compositor-xrender.c b/src/compositor/meta-compositor-xrender.c
index 6055655..75162ed 100644
--- a/src/compositor/meta-compositor-xrender.c
+++ b/src/compositor/meta-compositor-xrender.c
@@ -1599,7 +1599,7 @@ paint_windows (MetaCompositorXRender *xrender,
                                 x, y, wid, hei);
 
               XRenderComposite (xdisplay, PictOpAdd, cw->picture,
-                                None, root_buffer, 0, 0, 0, 0,
+                                cw->alpha_pict, root_buffer, 0, 0, 0, 0,
                                 x, y, wid, hei);
             }
           else if (cw->mode == WINDOW_ARGB && cw->mask != None)
@@ -1618,7 +1618,7 @@ paint_windows (MetaCompositorXRender *xrender,
                                 x, y, wid, hei);
 
               XRenderComposite (xdisplay, PictOpAdd, cw->picture,
-                                None, root_buffer, 0, 0, 0, 0,
+                                cw->alpha_pict, root_buffer, 0, 0, 0, 0,
                                 x, y, wid, hei);
 
               XFixesIntersectRegion (xdisplay, clip, cw->border_clip, client);