This CL adds namespaces to AECM. Bug: webrtc:5298 Change-Id: Ibb124ef9eb46c4bd762847b6763b37a6eeb85433 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/171105 Commit-Queue: Per Åhgren <peah@webrtc.org> Reviewed-by: Sam Zackrisson <saza@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30849}