The recent change to use the top-level non-window-manager Window drawable
coordinates from xwl_window_check_resolution_change_emulation() in
combination with only calling it on a resize when the top-level window
is moved breaks things with mutter/gnome-shell.

When fullscreening a X11 window, mutter moves its window-decoration Window
wrapping the top-level Window to the monitor's origin coordinates (e.g. 0x0)
last. This updates the top-level's drawable coordinates, but as the
actual MoveWindow is called on the wrapper Window and not on the toplevel
we do not call xwl_window_check_resolution_change_emulation() and we never
enable the viewport.

This commit fixes this by also calling
xwl_window_check_resolution_change_emulation() if the Window being moved
is an xwl_window itself.

Acked-by: Olivier Fourdan <ofourdan@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>