GitLab

- Use nullptr
- Use std::make_unique()
- Use auto
- Use = default;
- Use modern copyright notice
- Stop using DISALLOW_COPY_AND_ASSIGN()

Bug: 1010217
Change-Id: Ib3e5ec1715b33325f11f391bb749e3e014c1ba4d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2495978Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#821010}