This CL changes the aggregation of the matched filter delay estimates in AEC3 to using a histogram approach. Bug: chromium:773541,webrtc:8379 Change-Id: I5322c65858188599397ef5716fecdebc34852e6a Reviewed-on: https://webrtc-review.googlesource.com/8261 Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org> Commit-Queue: Per Åhgren <peah@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20234}