[ServiceWorker] Disable http URLs when there are no clients (#671)

Per https://github.com/slightlyoff/BackgroundSync there is this idea that when a service worker is running in the background and there is no UI we should not allow insecure fetches.

Should we annotate the environment settings object in some way? Fetch can then check this new variable and return a network error in case of an http URL.

(Presumably we will disallow insecure `WebSocket` at all times?)

---
Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/671