tree b951d09994f7aaa588a9986a3c4d160efe53a486
parent b0090e97f0640c5e21d7ad2bb616b22940c03469
author Morten Stenshorne <mstensho@chromium.org> 1643208484 -0800
committer Blink WPT Bot <blink-w3c-test-autoroller@chromium.org> 1643208886 -0800

Disable fragment traversal correctly when block frag is enabled.

Once we've entered legacy multicol, nothing inside should do fragment
traversal. The legacy multicol pre-paint code might create multiple
FragmentData entries for monolithic forced LayoutNG objects (such as
math and custom layout), because legacy layout doesn't really understand
what monolithic means.

This worked fine when LayoutNGBlockFragmentation was disabled, since
we'd always disable fragmentation inside multicol then. But when the
feature was enabled, we would allow fragment traversal of LayoutNG
subtrees inside legacy multicol. Don't do that.

The new test crashes with LayoutNG disabled (regardless of this fix),
since the test uses the CSS layout API, which isn't supported when
LayoutNG is disabled. Just skip it there.

Bug: 1289999
Change-Id: Iacddb22eb3df224ea57f988f37409bd57b5f200d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3412124
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Cr-Commit-Position: refs/heads/main@{#963498}