We hit this CHECK even though the format wasn't even L16, because we did the checked_cast before testing the codec name. BUG=chromium:760994 TBR=ossu@webrtc.org Change-Id: I382a2f841e51944495500f87650258024030d355 Reviewed-on: https://webrtc-review.googlesource.com/1224 Reviewed-by: Karl Wiberg <kwiberg@webrtc.org> Commit-Queue: Karl Wiberg <kwiberg@webrtc.org> Cr-Commit-Position: refs/heads/master@{#19835}