Dietrich's talk during today's battery optimization workshop gave me this idea. The use-case here is multiple web apps on a Firefox OS phone using XMLHttpRequest to retrieve data from a server (e.g. messaging apps getting new messages, social apps retrieving friends' activities, etc...). When those apps (or tabs in the case of a desktop browser) are hidden we might not honor them immediately so that we can gather a few and then send all of them in one go thus turning on the modem only once to serve all of them.

Bulk change to priority: https://bugzilla.mozilla.org/show_bug.cgi?id=1399258