1744171 - [wpt-sync] Sync PR 31865 - Remove 'font-size: 0' from some css-flexbox scrollbars reference cases.

Status: RESOLVED FIXED

(Core :: Layout: Flexbox, task, P4)

Description

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Sync web-platform-tests PR 31865 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/31865
Details from upstream follow.

Daniel Holbert <[e-mail]> wrote:

Remove 'font-size: 0' from some css-flexbox scrollbars reference cases.

The zero font-size is essentially non-functional, but it causes a slight
rendering difference in Firefox's scrollbar-thumb-sizing (and results in a test
failure), for what turns out to be good reasons:

Essentially, the scrollbar thumb is a reflection of the pagedown-distance; and
in Firefox, we use a slightly-larger pagedown-distance if the scrollport has a
sufficiently-small font size, because we only aim to have a few lines of
overlap between the old and new scrollport during a pagedown operation. And "a
few lines of overlap" is based on the scrollport's font-size. So the
pagedown-distance is dependent on the font-size, and therefore so is the
scrollbar thumb size.

(See https://bugzilla.mozilla.org/show_bug.cgi?id=1743924#c9 for more.)

Comment 1

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Pushed to try (stability) https://treeherder.mozilla.org/#/jobs?repo=try&revision=42bf2af818339ca9503aff3740abf5af9c98992a

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8fb675af670b
[wpt PR 31865] - Remove 'font-size: 0' from some css-flexbox scrollbars reference cases., a=testonly

Comment 3

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Test result changes from PR not available.

Comment 4

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/8fb675af670b