This CL adds robustness to avoid the AEC3 transparent mode to be incorrectly activated when -there is strong near-end noise -there is only low-level nearend activity. Bug: webrtc:9256,chromium:841193 Change-Id: I26c2759d163914eb85dc3d863da8acbf28cbb88d Reviewed-on: https://webrtc-review.googlesource.com/75511 Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org> Commit-Queue: Per Åhgren <peah@webrtc.org> Cr-Commit-Position: refs/heads/master@{#23191}