This CL adds a smooth rampup of the NLP gain in AEC3. Bug: webrtc:8361 Change-Id: I49aa75904751ffe9150db1572271fe7a26232449 Reviewed-on: https://webrtc-review.googlesource.com/7740 Commit-Queue: Per Åhgren <peah@webrtc.org> Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org> Cr-Commit-Position: refs/heads/master@{#20213}