Telemetry data says the median time for this one is 21.94ms. Terrible. :(

This should be relatively easy to fix -- the only concern I could think of would be someone deleting a dictionary out from under us. This is probably worse than the sync message per-word in terms of jank since at least that one is capped by some manually-written timeout code.

I will remove most case to use Msg_SetDictionary by bug 1330912.

So bug 1330912 is fixed. Do you think this is still an issue?

(In reply to Kan-Ru Chen [:kanru] (UTC+8) from comment #3) > So bug 1330912 is fixed. Do you think this is still an issue? Firefox doesn't use setCurrentDictionary, but this is still used on tests. Also, some addons use it.

(In reply to Makoto Kato [:m_kato] (PTO: 4/30-5/5) from comment #4) > (In reply to Kan-Ru Chen [:kanru] (UTC+8) from comment #3) > > So bug 1330912 is fixed. Do you think this is still an issue? > > Firefox doesn't use setCurrentDictionary, but this is still used on tests. > Also, some addons use it. The add-ons case won't be an issue after Firefox 57, since those won't run on Firefox release. It's just annoying that we will probably keep seeing this in the telemtry data forever since even after 57 WebExtension experiments can still access this API as long as it exists. :-( (I wish we had a way to actually restrict an API only to our tests...) I would say we should close this bug, since there is nothing more left to do for Firefox 57 as far as I can tell. What do you think?

Yes, we should close this bug. This IPC is tests and old addons only.