CREDENTIAL: Tighten zero-click requirements.
We should sign-in without user mediation only in completely unambigious
circumstances. This patch tighten things up a bit such that multiple
'PasswordForm' objects _always_ prevents zero-click sign-in, rather than
the existing behavior which prevents iff more than one form has the
'skip_zero_click' property set to 'false'.
BUG=528855
R=vabr@chromium.org
Review URL: https://codereview.chromium.org/
1312773006
Cr-Commit-Position: refs/heads/master@{#347615}