GitLab

Updates some enums to enum classes, uses class member initializers, add
unique_ptr to more cases.

Change-Id: Iddca37cfba27a1fe7e2d74d73ced4c360769562f
Reviewed-on: https://chromium-review.googlesource.com/822524
Commit-Queue: Brett Wilson <brettw@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523651}