Add hotword detection to media perception private API.

BUG=chromium:833595

Change-Id: Ifed53adb6baef9e34c50cf09b71703d018f1617b
Reviewed-on: https://chromium-review.googlesource.com/1015506
Reviewed-by: Steven Bennetts <stevenjb@chromium.org>
Reviewed-by: Toni Barzic <tbarzic@chromium.org>
Commit-Queue: Wei Guan <weigua@chromium.org>
Cr-Commit-Position: refs/heads/master@{#552246}
4 files changed