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- Adds a histrogram and metric collection for the authenticaion method
that a user uses.

Bug: chromium:891902
Change-Id: I6f3a9e81ec3983750d006c93fa79b147c83fc98b
Reviewed-on: https://chromium-review.googlesource.com/c/1262971
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Reviewed-by: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#598689}