Allow freezing and discarding of tabs that update the title or favicon

[philipwalton]

I'm opening this as a placeholder to track the progress of Fadi's Service Worker Background APIs proposal as a potential solution to this problem.

From the proposal:

Around 60% of all tabs either update their title, favicon or play some sound while in the background. Those actions prevents the tab from getting discarded when a browser is running under critical resources. This proposal enables doing those actions for any backgrounded tab whether discarded, frozen or active using a Service Worker. (Current proposal omits the audio APIs)

Related discussion:
w3c/ServiceWorker#626