Correctly identify overflow direction inside flexbox.

BUG=961286
R=cbiesinger@chromium.org

Change-Id: I6c827744b69a5f2d36c0cc219fe8e490fe851f55
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1618017
Commit-Queue: Stefan Zager <szager@chromium.org>
Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661195}
4 files changed