ref: b7654afb6baba32d9dcafed558cb20575e692ae5
parent: c0c0edd9d73b4d953d539669123706ee97468e89
parent: e15fedb9258251bbb07def57e49e2bd1e0c4c538
author: Jacky Chen <jackychen@google.com>
date: Mon Dec 14 19:41:23 EST 2015
Merge "Add "unknown" status for noise estimation."