[LayoutNG] Ensure self-collapsing block relayout when ancestor resolves.

This bug was a combination of older code before we had "forced" BFC
block-offsets.

We didn't correctly detect when we had a self-collapsing block (which
had floats within it) that needed relayout if the initial estimate
was wrong.

This makes sure we give ourselves enough information to detect these
cases.

Bug: 980803
Change-Id: Id1ea5e10d819cb4509fd7664564b75b876f0f7cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1690720
Commit-Queue: Ian Kilpatrick <ikilpatrick@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Reviewed-by: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#675729}
2 files changed