GitLab

There has been confusion about the third-party review process. Try to
clarify that chromium-third-party is about licensing review, that the
reviewers may simply leave a comment, and that they are not expected to
be able to approve a change.

Change-Id: I8461f9b416f8d76542230beb770a2cf8f5c44d6f
Reviewed-on: https://chromium-review.googlesource.com/c/1338477Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Reviewed-by: Adam Langley <agl@chromium.org>
Commit-Queue: Adam Langley <agl@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609820}