The boilerplate that I used for all the callbacks-to-promises

conversions works in almost every case, but the ready() method is a

bit special because the callback name is ready instead of success.

The promiseToCallbacks adapter handled this, but the call sites inside

of the ready methods weren't testing for that callback name, so it

wouldn't work properly when calling in the old style.

Used an extension that called ready() on a draft review using the

callbacks style instead of promises. Saw that it worked correctly.