[ServiceWorker] openWindow(url)'s same origin check should be done against the origin of the final response's url? (#646)

Pointed out by @inexorabletash at https://codereview.chromium.org/984853003/diff/1/content/browser/service_worker/service_worker_version.cc#newcode1155:
> An on-origin request could end up redirecting to an off-origin location. An off-origin request could
end up redirecting to an on-origin - even controlled - location.

We're currently check it against the origin of the original request's url. (step 5.4 of [openWindow](https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html#clients-openwindow)) Should we check it against the origin of the final response's url?

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Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/646