Improving support for Android Audio Effects in WebRTC.
Now also supports AGC and NS effects and adds the possibility
to override default settings.

R=magjed@webrtc.org, pbos@webrtc.org, sophiechang@chromium.org
TBR=perkj
BUG=NONE

Review URL: https://codereview.webrtc.org/1344563002 .

Cr-Original-Commit-Position: refs/heads/master@{#10030}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: c14f5ff60fb0c42c97702de112a9e8f1eccba574