henrika f06f35a161 Adds logging of native audio levels and UMA stats to track issues.
This changes added a simple measurement of levels "close to the audio hardware"
both for playout and for recording. These levels are logged once each 10 seconds.

It also adds WebRTC.Audio.RecordedOnlyZeros UMA stat and it is updated at
destuction. It will report true iff all reported recording leves are zero.

BUG=NONE
R=peah@webrtc.org

Review URL: https://codereview.webrtc.org/2328433003 .

Cr-Commit-Position: refs/heads/master@{#14160}
2016-09-09 12:23:24 +00:00
..