GitLab

Avoid creating a default virtual authenticator if the browser is not
running layout or WPT tests under content shell. This is not necessary
and confusing for anyone using the ChromeDriver API.

Fixed: 1019934
Change-Id: I4fc9f8a997df1f3c8bbf9120b6c1c1268259858c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1891466
Commit-Queue: Nina Satragno <nsatragno@chromium.org>
Reviewed-by: Martin Kreichgauer <martinkr@google.com>
Cr-Commit-Position: refs/heads/master@{#711523}