The reasoning for using a commit handler is to ensure that all paths for
output changes are correctly handled. With the centralized modeset
infrastructure in place, we can move the logic there. This allows us to
be smarter and avoid extraneous arranges, output manager updates and
transaction commits.
The side-effect is a minor duplication for the special-case
request_state, but the shared path will be relied upon further in future
commits to justify this duplication.
Kenny Levinsen