commit 0031e1b35868b6e3c3ecc05880f4fd77562b022d
author Morten Stenshorne <mstensho@chromium.org> Wed Oct 02 18:10:42 2019
committer Commit Bot <commit-bot@chromium.org> Wed Oct 02 18:10:42 2019
tree 0bce86cb9d5a34adfcc34f6a3a88ac7f718d8d5e
parent 9ed2fda9340a23d7399b35908de48e6bc222dfec

[LayoutNG] Support 'avoid' for break-before and break-after.

This adds layout engine support for break avoidance between block
children, if the LayoutNGBlockFragmentation feature is enabled. This
feature is still not shipping, and it is also worth noting that fragment
painting needs some work before we can paint and hit-test this properly
(which is a general issue for LayoutNGBlockFragmentation, not break
avoidance in particular).

The solution is built on top of NGEarlyBreak, which can set up possible
breakpoints before and inside blocks. Another important change is the
introduction of "break appeal", i.e. how attractive a possible
breakpoint is. Previously this was a binary thing; the break was either
considered good or last-resort. Now we set appeal, which will decrease
by rule violation severity.

Bug: 223068, 829028
Change-Id: I7bb19028821eaf380c70c7bd92b3338f47124dd3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1831804
Commit-Queue: Morten Stenshorne <mstensho@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Reviewed-by: Ian Kilpatrick <ikilpatrick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#702108}