Enable client cert auth for sign-in frame StoragePartition

Enable client certificate authentication in the sign-in profile for
the StoragePartition which is currently used by the sign-in frame.
Additionally, wire up the DeviceLoginScreenAutoSelectCertificateForUrls
policy to content settings on the sign-in screen.

BUG=723849
TEST=browser_tests --gtest_filter=WebViewClientCertsLoginTest.*

Change-Id: Ic5345bc3446c621008088909771c6eca445aa3f3
Reviewed-on: https://chromium-review.googlesource.com/790295
Commit-Queue: Pavol Marko <pmarko@chromium.org>
Reviewed-by: Ryan Sleevi <rsleevi@chromium.org>
Reviewed-by: Maksim Ivanov <emaxx@chromium.org>
Reviewed-by: Ryan Hamilton <rch@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521232}
10 files changed