[mutter] renderer-x11-nested: Use rounded width/heights for fb size

[Jonas Ådahl <jadahl src gnome org>]

commit c5471e5b8b1e493947e97659dda244a7b21ce629
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Nov 22 00:59:59 2018 -0600

    renderer-x11-nested: Use rounded width/heights for fb size
    
    https://bugzilla.gnome.org/show_bug.cgi?id=765011

 src/backends/x11/nested/meta-renderer-x11-nested.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/src/backends/x11/nested/meta-renderer-x11-nested.c 
b/src/backends/x11/nested/meta-renderer-x11-nested.c
index b29b9c69e..71a85a8c2 100644
--- a/src/backends/x11/nested/meta-renderer-x11-nested.c
+++ b/src/backends/x11/nested/meta-renderer-x11-nested.c
@@ -202,8 +202,8 @@ meta_renderer_x11_nested_create_view (MetaRenderer       *renderer,
       width = logical_monitor->rect.width;
       height = logical_monitor->rect.height;
     }
-  width *= view_scale;
-  height *= view_scale;
+  width = roundf (width * view_scale);
+  height = roundf (width * view_scale);
 
   fake_onscreen = create_offscreen (cogl_context, width, height);