Hello Frederick,
Sorry for late response. Wake Lock API as specified inhttp://www.w3.org/TR/wake-lock/is implemented in Yandex Browser as an experimental feature, upstreaming to Chromium is currently in progress.
The implementation includes Javascript tests (which I guess are browser-neutral) and Chromium-specific internal tests.
We have identified no issues during implementation, but there's been some issues raised by other users at https://github.com/w3c/wake-lock/issuesregarding the interface (e.g. whether it would be better to put the API to Screen or Window or Navigator instead of Document).
As for FPWD publication, I think this is already done athttp://www.w3.org/TR/wake-lock/, or am I missing something?
Kind regards,
Andrey Logvinov