This is a reland of 9dda1b3a484ebeef921e419406402039f3852427
Original change's description:
> Correct AEC3 multichannel functionality activation
>
> This CL corrects the AEC3 multichannel activation
> to also work for the case when a factory is used
> for the activation.
>
> Bug: webrtc:10913
> Change-Id: Ic2807d8bcef759261fde14447cff30633ba248dc
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158794
> Commit-Queue: Per Åhgren <peah@webrtc.org>
> Reviewed-by: Sam Zackrisson <saza@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#29676}
Bug: webrtc:10913
Change-Id: I1cb3d0de61ea0b299158ca85433f2442c65c196f
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158886
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29690}
4e5c709ed4