GitLab

left/padding/width/height...
Replaced NGSizeIndefinite with Optional<LayoutUnit>

Fixed a couple of minor bugs where AvailableSize was incorrect.

Passing ~30 more tests.

BUG=635619

Review-Url: https://codereview.chromium.org/2616613003
Cr-Commit-Position: refs/heads/master@{#441881}