merge_pr_50

Add test for negative inline margin + fit-content

Also fixes a DCHECK that incorrectly hits.

Bug: 1028817
Change-Id: I43cb472031f4d3842eb302a5460e6dea047120e6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1941451
Reviewed-by: Ian Kilpatrick ikilpatrick@chromium.org
Reviewed-by: Yoshifumi Inoue yosin@chromium.org
Commit-Queue: Koji Ishii kojii@chromium.org
Cr-Commit-Position: refs/heads/master@{#719890}