Again, I strongly recommend that if you care about this, you look through the issue on the BMO (especially see depends on and blocks), figure out what the next step is, and do it :)
I suspect it would not take very much time at all, although there could be a reasonable amount of waiting for replies from Mozillians.
The problem is bureaucratic - the schedules of those involved rarely overlap, and they have very little motivation to work on it.
The meta bug for the API is here: https://bugzilla.mozilla.org/show_bug.cgi?id=1215061
Again, I strongly recommend that if you care about this, you look through the issue on the BMO (especially see depends on and blocks), figure out what the next step is, and do it :)
I suspect it would not take very much time at all, although there could be a reasonable amount of waiting for replies from Mozillians.