A while ago, I used to have some kind of App or service that would automatically unmount a dmg file whenever I put the dmg file into the trash. This was really convenient, but I've since reinstalled OS X, and I've completely forgotten the name of the app that provides this useful feature. I still have backups of my old system, but I have no idea where to look. So, does anyone know of an app that provides this feature?
(Note: There are plentiful tutorials on how to achieve the reverse, i.e. auto-trash on eject, but this is not what I'm looking for.)