tl;dr:
https://groups.google.com/a/chromium.org/forum/#!forum/embedder-dev/join
Last month was BlinkOn, and I met lots of people who are embedding Chromium to accomplish cool things. I'm one of the people who works on the content team, which allows Chromium to be embedded, and I realized that while we have chromium-dev@ and blink-dev@, which are great places to talk about working on the Chromium code base itself, there's no good place to talk about embedding Chromium and the changes that occasionally happen there.
So I established embedder-dev@. If you work on a Chromium embedder, I invite you to join. If you work on what we currently call the "Content API", I invite you to join.
The embedder interface has undergone small changes over the years, but big changes are going to happen (think PlzNavigate and Dmitri's "Embedder API 2.0" ideas). I want to make sure that there's a central place that these discussions and heads-up can happen so that no one is surprised.
Hope to see you there soon!
Avi