GitLab

Implementation: https://screenshot.googleplex.com/4Q2LOWL28un
Mock: https://screenshot.googleplex.com/iNV6JAtE9t9

The CL also makes a change to <site-favicon> to allow embedding it as a
round icon.

Bug: 1102294
Change-Id: I70b702a1404b7c20bd0df65f7b0db06d3c999d13
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2287297Reviewed-by: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Reviewed-by: Friedrich [CET] <fhorschig@chromium.org>
Commit-Queue: Victor Vianna <victorvianna@google.com>
Cr-Commit-Position: refs/heads/master@{#796317}