One of the biggest security issues on X11 was that any application could
take screenshots. On Wayland we addressed this by making the screenshot
process interactive. The user has to confirm explicitly that a
screenshot is taken. But our API still allows to create a screenshot and
save it directly to a temporary file. It shows a notification, but
nevertheless it is a small security issue.
Thus this change addresses it by sending a dbus error in case the
methods are called on Wayland.