Add an extended filter option to audioproc.
Add an extended filter option to audioproc.

R=bjornv@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2609005

Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 22858d4785f245c5a61941c328ffeef6075efb8c

sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc,sippet/webrtc