This CL removes the unused coherence computation from AEC3. This CL only removes unused code, the output of AEC3 does not change. Bug: webrtc:8671 Change-Id: Ie127c5ec64e29414f1e1570511d57a4d09fc9145 Reviewed-on: https://webrtc-review.googlesource.com/95650 Reviewed-by: Per Åhgren <peah@webrtc.org> Commit-Queue: Gustaf Ullberg <gustaf@webrtc.org> Cr-Commit-Position: refs/heads/master@{#24403}