GitLab

Mostly adds = default and changes typedef to using.

Change-Id: Ic9d8ab0caf10acf8b86e97a02d5dcd15764d3148
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2532023Reviewed-by: Keith Lee <keithlee@chromium.org>
Commit-Queue: Darren Shen <shend@chromium.org>
Cr-Commit-Position: refs/heads/master@{#827667}