Standalone COEP spec should be gutted now that HTML contains COEP

[domenic]

The standalone COEP spec is at https://wicg.github.io/cross-origin-embedder-policy/. It should no longer exist, since the spec has been upstreamed elsewhere.

Work on this will require cooperation from someone with write access to https://github.com/WICG/cross-origin-embedder-policy/ , to un-archive it and accept changes to the index.bs and index.html files there.

This work consists of several stages:

1. Remove redundant and confusing normative content

The normative content of this spec has almost all moved into HTML and Fetch, so we should delete these obsolete definitions and algorithms.

• Delete https://wicg.github.io/cross-origin-embedder-policy/#framework
• Move https://wicg.github.io/cross-origin-embedder-policy/#integration-sw into the Service Worker spec
• Then delete https://wicg.github.io/cross-origin-embedder-policy/#integrations

2. Move or delete non-normative content

What remains is the non-normative content in:

• https://wicg.github.io/cross-origin-embedder-policy/#intro
• https://wicg.github.io/cross-origin-embedder-policy/#impl-considerations

If we completely delete the spec, this content would be lost. Maybe that is fine. Or maybe we want to preserve it. If it is valuable, it could be moved to any of the following locations:

• https://html.spec.whatwg.org/#coep
• https://github.com/WICG/cross-origin-embedder-policy/blob/master/README.md
• https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cross-Origin-Embedder-Policy

If this moves to https://html.spec.whatwg.org/#coep, some editing will be required, e.g. to fit with HTML's editorial style, or to stop talking about the header as a proposal and instead talk about it as a part of the established standard.

At a glance, my guess is that "Implementation Considerations" is not necessary to keep, but "Introduction" could be useful.

3. Redirect the spec

At this point, there should be no content left in https://wicg.github.io/cross-origin-embedder-policy/. Replace it with a stub that redirects to HTML, like this example.