This CL will change the behavior when enabling Delay Agnostic AEC through the media constraint (and AudioOption delay_agnostic_aec)
FROM
Use DA-AEC instead of AECM if there is no HW-AEC
TO
Use DA-AEC even if there is a HW-AEC
Before this change the user will not really know if the Delay Agnostic AEC is running or not, so it is more intuitive if the option overrides the built-in one if the user has asked for it.
BUG=4472
TESTED=locally with a modified AppRTCDemo app
R=tommi@webrtc.org
Review URL: https://webrtc-codereview.appspot.com/49859004
Cr-Commit-Position: refs/heads/master@{#9147}
ccfc93913c