This CL adds the missing support for multi-channel in the code that provides an optional and configurable delay to be added to the microphone signal. The CL also makes the creation of the delay object conditional on the need for that support (this is important since this adds a significant heap memory footprint) Bug: webrtc:11314,chromium:1045910 Change-Id: I92d577e31af830945fe9d5ca2032000aad4266be Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/167525 Commit-Queue: Per Åhgren <peah@webrtc.org> Reviewed-by: Sam Zackrisson <saza@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30392}