Settings: Convert privacy_page/ to Polymer class syntax, part3.

Bug: 1206112
Change-Id: Ie18fe12a74ce62abccba0bc91124a0e08b9ef741
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2984963


Commit-Queue: dpapad <dpapad@chromium.org>
Commit-Queue: Theodore Olsauskas-Warren <sauski@google.com>
Auto-Submit: dpapad <dpapad@chromium.org>
Reviewed-by: Theodore Olsauskas-Warren <sauski@google.com>
Cr-Commit-Position: refs/heads/master@{#896454}