This is a meta bug, need to file bugs for the specific places that need to be converted.
Under mustash/mash, code in ash runs in a separate process. Code in the browser process must be converted to use the mojo interfaces in ash/public/interfaces to talk to ash.
Practically, this usually means eliminating access to ash::Shell::Get() and its controllers.
Comment 1 by jamescook@chromium.org
, Jan 5 2017