An X11 window manager might add a chain of parent windows when reparenting to a
decoration window.

That is for example the case for KWin, which reparents client windows to one
decoration and another wrapper parent window.

Account for that by a recursion into the tree. For now assume as before that
all X11 window managers reparent with one child only for these parent windows.

Changes by Hans de Goede:
- Move the xwl_window_is_toplevel() from a later patch in this series here
  as it really belongs together with these changes
- Drop no longer necessary xwl_window argument from window_get_none_wm_owner
  parameters

Signed-off-by: Roman Gilg <subdiff@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Olivier Fourdan <ofourdan@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>