Spec name #82

In response to w3ctag/design-reviews#279

I find it a bit confusing that it is called background fetch.

First of all, I am afraid that people who look to do long running uploads won't find the feature due to the name. But I also find the background term a bit confusing, especially because to most developers, the Service Worker already runs in the background, so now we have something running in the background of the background.

What I really believe this is, is a transfer manager for async transfers that can outlive service worker lives. It is more about long running than it is about background. I would probably go with something like Long running transfers.

With that in mind, we could also rename backgroundfetch* and backgroundFetch to transfer, and we avoid the double fetch in await registration.backgroundFetch.fetch(id, requests, options); which would become await registration.transfer.fetch(id, requests, options);. transferManager might be another suggestion.

Event names would also be shorter, eg. backgroundfetchcomplete vs transfercomplete