Filing a bug as a follow-up of the offline discussion with hpayer@, chrisha@, and gab@.

Currently IsolateInBackgroundNotification is sent to V8 when all tabs of the isolate are on background.

It does not take into account audio information, so V8 may introduce jank to a page playing audio on background.

In order to account for audio, we need to send the notification from the resource coordinator service which has visibility and audio information for all pages.

This requires mojo connection from the resource coordinator to each renderer process.