GitLab

This pref was only read in one place (chrome_content_browser_client),
to check if the user is signed in.

TBR=jzw

Change-Id: I491b06b5fefd9fef5d7dc27a38a652870c1a5cc7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1795330
Commit-Queue: David Roger <droger@chromium.org>
Reviewed-by: Monica Basta <msalama@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695988}