Add "masked" property to TableViewTextItem to support showing masked text.

PasswordDetailItem can display an uneditable string as plain text("abc")
or masked text("XXX"). This CL add the same functionality in
TableViewTextItem to avoid creating another class like
TableViewPasswordItem. This is a preparation work for migrating Settings
from MDC to UIKit.

Bug: 894791
Change-Id: I34538659d6879246c66e9aafd4d88cb8d7822f3c
Reviewed-on: https://chromium-review.googlesource.com/c/1346151
Commit-Queue: Yi Su <mrsuyi@chromium.org>
Reviewed-by: Eric Noyau <noyau@chromium.org>
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Cr-Commit-Position: refs/heads/master@{#610414}
6 files changed