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}