Re-land Reformat comments in core/layout up until LayoutBox

This reverts commit 64f8e6ee53f1542634b9bb32cc84f2e24356fee3.

BUG=563793
R=ikilpatrick@chromium.org
NOTRY=true

Review-Url: https://codereview.chromium.org/2398623003
Cr-Commit-Position: refs/heads/master@{#423661}
29 files changed