[LayoutNG] Don't use the margin-strut in the OOF static-position if zero-height.
This patch does two things:
- Doesn't include the margin strut in the OOF static-position if we are
currently going to be a zero-height-div.
This gives a static block offset of 0 relative to its immediate
parent, which is correct.
- Positions zero-height fragments using *their* end margin strut. Not
the previous margin strut.
BUG=635619
Review-Url: https://codereview.chromium.org/2868523002
Cr-Commit-Position: refs/heads/master@{#469882}
3 files changed
