1914970 - Consider making DOMRect::SetLayoutRect use the same app unit -> float conversion as the rest of Gecko

Status: ASSIGNED

(Core :: DOM: CSS Object Model, defect, P3)

Description

[Emilio Cobos Álvarez [:emilio]]

I just tried to do this in bug 1914831 (and bug 1640441), but it causes some WPT failures (mathml/presentation-markup/mrow/inferred-mrow-baseline.html), and some browser test failures which seem potentially a pre-existing issue looking at MozRichListBox (browser/components/places/tests/browser/browser_bug631374_tags_selector_scroll.js).

Over-all I think it is worth doing, but let's move this to a separate bug to deal with failures / backouts as needed.

Comment 1

[Emilio Cobos Álvarez [:emilio]]

Attachment: Bug 1914970 - Try to use consistent rounding in DOMRect::SetLayoutRect. r=#layout

Otherwise we can get into states where identical numbers end up being
different from the ones exposed in other APIs.

This is a somewhat risky change, so gate it behind a pref.

This fixes the issue, but given it's a tricky change I'll also add a
workaround to avoid depending on it on the front-end.

Comment 2

[Emilio Cobos Álvarez [:emilio]]

https://treeherder.mozilla.org/jobs?repo=try&revision=8ca656aa931c2db99ef6b1c52199ca484ac66e54

Comment 3

[Phabricator Automation]

Comment on attachment 9420829 [details]
Bug 1914970 - Try to use consistent rounding in DOMRect::SetLayoutRect. r=#layout

Revision D220126 was moved to bug 1914831. Setting attachment 9420829 [details] to obsolete.