Add cross-site ancestor flag to environment. (privacycg/storage-parti…

[wanderview]

…tioning#25)

• At least two implementers are interested (and none opposed):
  • …
  • …
• Tests are written and can be reviewed and commented upon at:
  • …
• Implementation bugs are filed:
  • Chrome: …
  • Firefox: …
  • Safari: …
  • Deno (only for timers, structured clone, base64 utils, channel messaging, module resolution, web workers, and web storage): …
  • Node.js (only for timers, structured clone, base64 utils, channel messaging, and module resolution): …

(See WHATWG Working Mode: Changes for more details.)

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/browsers.html ( diff )
/browsing-the-web.html ( diff )
/webappapis.html ( diff )
/window-object.html ( diff )
/workers.html ( diff )

[wanderview]

This is a speculative PR for privacycg/storage-partitioning#25. It lays the groundwork for adding the bit to the storage key in a separate PR. Also, if this lands we need a follow-up to set the environment bit when a service worker is created.

[johannhof]

I realized that this is probably what we need for #9729, @annevk let's try to figure out what's missing here