1729891 - [wpt-sync] Sync PR 30419 - Avoid suboptimal breaks inside a column row when appropriate.

Status: RESOLVED FIXED

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

Description

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

Sync web-platform-tests PR 30419 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/30419
Details from upstream follow.

b'Morten Stenshorne <[e-mail]>' wrote:

Avoid suboptimal breaks inside a column row when appropriate.

Set a minimum appeal for breaks inside a nested multicol container, if
the row is past the block-start of the outer fragmentainer. If there's
content that breaks suboptimally (with a lower appeal than any previous
breaks), push such content ahead of us, so that it ends up in the next
outer fragmentainer. There may be more space there, so that the
suboptimal break may be avoided.

Propagate the lowest appeal among all column breaks to the multicol
fragment builder, so that an ancestor can decide to break before the
entire multicol container, if that would be better. This currently only
works if the multicol container itself breaks, since break appeal is
stored in the break tokens. A follow-up CL will fix this (by storing it
in NGLayoutResult instead), so that we'll also detect suboptimal breaks
inside a nested multicol container that didn't break in the outer
fragmentation context.

This doesn't fix any existing tests by itself, but will contribute to
it. A follow-up CL will fix some remaining problems, so that quite a few
existing tests will finally pass.

Bug: 829028
Change-Id: I4a09e2163aa194780be986f358283d4e8da9a115
Reviewed-on: https://chromium-review.googlesource.com/3149995
WPT-Export-Revision: 7dbee704adfb150f40dd78f76daecf5b5855f517

Comment 1

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

Pushed to try (stability) https://treeherder.mozilla.org/#/jobs?repo=try&revision=26faaf5fe653cbb32892ba2fa98735262991cb1a

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/e9b6122764d2
[wpt PR 30419] - Avoid suboptimal breaks inside a column row when appropriate., a=testonly
https://hg.mozilla.org/integration/autoland/rev/780cf1dbd38d
[wpt PR 30419] - Update wpt metadata, a=testonly

Comment 3

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

Test result changes from PR not available.

Comment 4

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/e9b6122764d2
https://hg.mozilla.org/mozilla-central/rev/780cf1dbd38d