Isolated Testing
What's happening
The Chrome team is in the process of retro-fitting the ability of running tests outside a checkout to scale out testing so the tests results are returned faster.
Design documents
The whole LUCI/Swarming/Isolate project lives in its own project at github.com/luci. The design docs on the wiki are a recommended reading since it gives background about the rationale why is it done in the first place.
User guide
I want to convert my test or use the infrastructure <- most likely this one.