There is a weird split where some of the chromite/third_party/ libs come via repo, and some are checked in.

I think it's better to just have everything checked in there. chromite is unusable without these python modules and is used standalone...

we have a strong interest to *not* commit swarming.client to the chromite repo

it's hard to say what contexts you're running into here whereby the swarming client is necessary.  if it's on the DUT, then it sounds like you want an ebuild to install the swarming.client as a standard python package ?

I decided to not depend on chromite's swarming_lib.py or the bundled swarming.client checkout at all.

The context here was on a lab server.

Since we don't have a good story for deploying chromite with its dependencies inside autotest, I'm just going to shy away from using chromite's library in this case.