JavaScript ShadowRealm proposal integration

[Ms2ger]

To replace #5339. Draft because I still need to iron out a few issues around module loading, and need to change what the global object looks like.

• [ ] At least two implementers are interested (and none opposed):
  • …
  • …
• [ ] Tests are written and can be reviewed and commented upon at:
  • …
• [ ] Implementation bugs are filed:
  • Chromium: …
  • Gecko: …
  • WebKit: …
  • 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): …
• [ ] MDN issue is filed: …
• [ ] The top of this comment includes a clear commit message to use.

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

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/browsing-the-web.html ( diff ) /dom.html ( diff ) /embedded-content.html ( diff ) /form-elements.html ( diff ) /index.html ( diff ) /infrastructure.html ( diff ) /media.html ( diff ) /nav-history-apis.html ( diff ) /references.html ( diff ) /scripting.html ( diff ) /structured-data.html ( diff ) /timers-and-user-prompts.html ( diff ) /webappapis.html ( diff ) /workers.html ( diff )

[Ms2ger]

I think this could benefit from review at this point

[littledan]

ShadowRealms reached 2.7 in TC39. Acceptance of this PR by WHATWG editors is a blocking requirement for Stage 3, though it probably shouldn't be landed until the Web API set is finalized.

@domenic @annevk @zcorpan Any thoughts/concerns?