Spec: https://github.com/whatwg/url/pull/763

Tests: https://github.com/web-platform-tests/wpt/pull/39069

Safari landed it to preview 168, so the keyword. https://webkit.org/blog/14106/release-notes-for-safari-technology-preview-168/

Implemented URL.canParse() static function for checking if a URL can be
parsed (instead of having to try wrap the constructor).

Avoids using an ErrorResult/Throws as it is not specified, and for
performance (see spec issue from linked PR).

All WPT tests for it now pass.

Spec PR: https://github.com/whatwg/url/pull/763
WPT tests: https://wpt.fyi/results/url/url-statics-canparse.any.html

Intent to prototype and ship: https://groups.google.com/a/mozilla.org/g/dev-platform/c/BWLpi4dqZOE

Backed out for causing wpt failures in /url/idlharness.any.worker.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/e8102aa8a372dee850fbac0e1bcf0157e60ccdec

Push with failures

Failure log ->

Sorry, missed some new WPT passes. Fixed.

https://hg.mozilla.org/mozilla-central/rev/1b2f34c70570

Release Note Request (optional, but appreciated)
[Why is this notable]: New function exposed to all sites (in window)
[Affects Firefox for Android]: Yes
[Suggested wording]: Added the new URL.canParse() function to allow easy and fast checking if URLs are valid and parseable.
[Links (documentation, blog post, etc)]: No docs yet as quite new.

Thanks, added a to the Fx115 Nightly release notes. Keeping the relnote? flag open to keep it on the radar for inclusion in our final release notes.

FF115 MDN docs can be tracked in https://github.com/mdn/content/issues/27170.
The work is all done, but in review.