Broken by https://codereview.webrtc.org/2750783004/. Since samples are two bytes each, only half of the buffer was being zeroed, leading to garbage noise. BUG=webrtc:7885,webrtc:7343 Change-Id: I46ecf90258b681ccdebbcfadd2e84ac6abadc9fe Reviewed-on: https://chromium-review.googlesource.com/593092 Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Commit-Queue: Jonathan Yu <yujo@chromium.org> Cr-Commit-Position: refs/heads/master@{#19194}