compositor: recompute output position on mode switch

When an output permanently changes its resolution, the output on the right
should be moved accordingly. We also add an event for output resizing so that
plugins can react when an output is resized.

Signed-off-by: David Fort <contact@hardening-consulting.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
2 files changed