GitLab

- Introduce LivenessBroker
- Fix IWYU
- Fix LSAN scope

Bug: 1056170
Change-Id: I7e685d0833932fa0e3e1a14dcf64e1fc48349461
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2642334
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#846025}