Add feedback PSD for the simplified NTP experiment

BUG=843585

Change-Id: I995039a1173771c91acc5dd04a60d6e1499ea9b2
Reviewed-on: https://chromium-review.googlesource.com/1062148
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559216}
4 files changed