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Most of the metrics were added to UKM in:
https://chromium-review.googlesource.com/c/chromium/src/+/939904
Some metrics were missed due to privacy review being stale.
This CL adds the remaining metrics after updating privacy doc

BUG=730783

Change-Id: Iec4cc7d6cc4f90c7fb57a9bd8cad23eef7e3dce9
Reviewed-on: https://chromium-review.googlesource.com/961538Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Commit-Queue: Siddhartha S <ssid@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543497}