Add new style to LoginPinView

Define two PIN keyboard styles and update view layout accordingly:
* Alphanumeric
Keys display digit and a part of the alphabet below. This is the
exact style of existing LoginPinView.
* Numeric
Keys only display digit, therefore keys height is different. This
is the new style.

Use Alphanumeric PIN style for login PIN input and Numeric PIN style
for parent access code input.

Bug: 911326
Test: LoginPinViewTest
Change-Id: Id164d8580cd64db6891348b5de4638be52ab5c0d
Reviewed-on: https://chromium-review.googlesource.com/c/1483675
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636683}
5 files changed