[gtk/resizing-fixes] wayland: Use shadow size from GdkToplevelSize

[Matthias Clasen <matthiasc src gnome org>]

commit bc05b0bba57aa6a1cd866f82d17261bb60cc0104
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Aug 12 08:00:11 2020 -0400

    wayland: Use shadow size from GdkToplevelSize

 gdk/wayland/gdksurface-wayland.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
---
diff --git a/gdk/wayland/gdksurface-wayland.c b/gdk/wayland/gdksurface-wayland.c
index 9444f46265..9ef412fab8 100644
--- a/gdk/wayland/gdksurface-wayland.c
+++ b/gdk/wayland/gdksurface-wayland.c
@@ -1300,8 +1300,11 @@ configure_surface_geometry (GdkSurface *surface)
   gdk_toplevel_notify_compute_size (GDK_TOPLEVEL (surface), &size);
   width = size.width;
   height = size.height;
-  g_warn_if_fail (width > 0);
-  g_warn_if_fail (height > 0);
+
+  impl->margin_left = surface->shadow_left = size.shadow_left;
+  impl->margin_right = surface->shadow_right = size.shadow_right;
+  impl->margin_top = surface->shadow_top = size.shadow_top;
+  impl->margin_bottom = surface->shadow_bottom = size.shadow_bottom;
 
   layout = impl->toplevel.layout;
   if (gdk_toplevel_layout_get_resizable (layout))