Expose URLPattern everywhere

[ptomato]

I've drafted a set of criteria for which interfaces to expose universally on all globals, at
w3ctag/design-principles#510. URLPattern looks like it fits those criteria and is useful to have in any environment.

• At least two implementers are interested (and none opposed):
  • …
  • …
• Tests are written and can be reviewed and commented upon at:
  • Enable URLPattern tests in ShadowRealm web-platform-tests/wpt#49323
• Implementation bugs are filed:
  • Chromium: …
  • Gecko: …
  • WebKit: …
  • Deno: …
  • kenchris/urlpattern-polyfill: N/A
• MDN issue is filed: …
• The top of this comment includes a clear commit message to use.

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[jeremyroman]

Conceptually makes sense to me, but would like to see w3ctag/design-principles#510 settled.

Browsers (well, at the moment, Chromium) shipping this probably does imply a web-facing change albeit a minor one.

Does this confine the future evolution of URLPattern? For example, it says that anything that uses an event loop or I/O should not have [Exposed=*]. Would we be deciding, now, that no future members like that would be added (or, at least, that they would throw)? I don't anticipate anything like that, but want to be sure I understand all of the consequences.

[ptomato]

Thanks! I will proceed with writing tests and filing implementation bugs when the design-principles issue is settled, then.

I don't believe this would prevent adding members in future that wouldn't be exposed everywhere. For example, AbortSignal has a timeout member that is only exposed in Window and Worker, despite AbortSignal having [Exposed=*]. And if there's a good reason and all else fails, well, the design principle is a guide, not a requirement.