[ServiceWorker] navigations that are not intercepted should still allow interception on further redirects (#793)

After talking with @annevk, it seems the intention of the spec is that every redirect of a navigation should check for service worker interception again.  Currently the spec is quite vague about this.

Currently step 4.2 of HTTP Fetch unconditionally set skip-service-worker on the Request if a service worker does not intercept in step 3.  In the case of a navigation that redirects, this results in a Request with skip-service-worker being set returning an opaque redirect back to the navigation spec logic.  The http spec navigation logic is somewhat vague about if a new Request is created or not.  The important question here is "does the skip-service-worker" flag propagate across redirects for the navigation?

To sidestep the http spec vagueness, @annevk has suggested we simply change HTTP Fetch step 4.2 to only set skip-service-worker if the RequestRedirect value is "follow".

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Reply to this email directly or view it on GitHub:
https://github.com/slightlyoff/ServiceWorker/issues/793