Goal is to ensure that unreviewed and untrusted code isn't sent through
CQ to try bots, by accident or through malicious intent.

R=kjellander@google.com
BUG=chromium:692613
NOTRY=True

Change-Id: If10d778b9c9866593a4c6c36216ed0e1c12fa1d5
Reviewed-on: https://chromium-review.googlesource.com/443546Reviewed-by: Henrik Kjellander <kjellander@chromium.org>
Commit-Queue: Andrii Shyshkalov <tandrii@chromium.org>