[css-viewport] Remove assert for offsetTop after modifying zoom property

[mrego]

There's no spec about what we should do with the scrollTop value after applying zoom. Which makes Firefox fail the test: css/css-viewport/zoom/scroll-top-test-with-zoom.html

Anyway checking that intermediate value is not relevant for this test, that is checking that the scrollTop value doesn't change when coming back to the initial zoom level. So this patch removes the assert checking that value.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1891910 for more details.

[chrishtr]

There's no spec about what we should do with the scrollTop value after applying zoom. Which makes Firefox fail the test: css/css-viewport/zoom/scroll-top-test-with-zoom.html

There is a spec for all of these in cssom-view. scrollTop doesn't say to do anything about zoom because it's not supposed to be affected by it (we resolved on this at the CSSWG).

[emilio]

@chrishtr doesn't it? The scroll* values should (and do, afaict) return the unzoomed coordinates, that's what was resolved on isn't it? In fact https://drafts.csswg.org/css-viewport/#zoom-om clarifies that when propagated to the viewport it shouldn't.

[chrishtr]

@chrishtr doesn't it? The scroll* values should (and do, afaict) return the unzoomed coordinates, that's what was resolved on isn't it? In fact https://drafts.csswg.org/css-viewport/#zoom-om clarifies that when propagated to the viewport it shouldn't.

Agreed!