Review Navigation API precommitHandler changes

[foolip]

Test List

web-platform-tests/wpt#51661 updated the Navigation API tests to "use new precommitHandler mechanism". web-platform-tests/wpt-metadata#7481 applied the renames.

These tests were touched and are still labeled for Interop 2025:
https://wpt.fyi/results/navigation-api/precommit-handler?q=label%3Ainterop-2025-navigation&run_id=6297615199371264&run_id=5119732632256512&run_id=5133616348921856&run_id=5144533484699648
https://wpt.fyi/results/navigation-api/scroll-behavior/manual-scroll-in-precommit-handler.html?q=label%3Ainterop-2025-navigation&run_id=6297615199371264&run_id=5119732632256512&run_id=5133616348921856&run_id=5144533484699648

These tests are no longer labeled, but maybe should be:
https://wpt.fyi/results/navigation-api/ordering-and-transition?q=%21label%3Ainterop-2025-navigation%20precommitHandler&run_id=6297615199371264&run_id=5119732632256512&run_id=5133616348921856&run_id=5144533484699648
https://wpt.fyi/results/navigation-api/precommit-handler?q=%21label%3Ainterop-2025-navigation&run_id=6297615199371264&run_id=5119732632256512&run_id=5133616348921856&run_id=5144533484699648

Rationale

Changes were made without a test change proposal, this is a retroactive review.

[zcorpan]

The precommitHander API is new and hasn't landed in the spec yet: whatwg/html#10919 Therefore it's not clear to me that it makes sense to include tests for it in the focus area.

The change also removed some tests (https://github.com/web-platform-tests/wpt-metadata/pull/7481/files). If we decide against including precommitHandler tests in the focus area, the removed test coverage should maybe be restored.

cc @farre @nt1m @noamr

[noamr]

precommitHandler is an API shape change for the "deferred commit" part of he navigation API, which was also not yet merged into the HTML spec. The deleted tests cover the previous shape of that API
It's a long requested addition to the navigation API so it would be sad to remove it from interop. OTOH it's not currently shipped in any browser and the spec PR is still not merged.

[nt1m]

Generally, unmerged spec changes should not be tested as part of interop, but I will defer to @annevk / @cdumez to check whether this change should be integrated into the spec.

[nairnandu]

cc: @natechapin for review

[foolip]

@natechapin @noamr might either of you be able to take a look at the tests and see if we should simply omit them from Interop 2025, or if we should restore the tests as they were before web-platform-tests/wpt#51661 and keep those in Interop 2025? (Or some mix of approaches.) Basically what we'd like is as much test coverage as possible without depending on things that aren't in the spec (or shipped in any browser) yet.

[noamr]

Non

Basically what we'd like is as much test coverage as possible without depending on things that aren't in the spec (or shipped in any browser) yet.

This implies that these tests should be removed from interop.

[foolip]

We discussed this in the Interop team meeting today and agreed to unlabel the tests linked up top, which now all test or depend on precommitHandler. We're not totally sure if the original change (web-platform-tests/wpt#51661) lost some coverage of Navigation API sans precommitHandler, but if someone discovers missing coverage down the line, we'll handle that through another test change proposal.