Mainly remove CHECKinitialized_ macro and AGC functionality. Also make
actual behavior clearer in some functions.
Bug: webrtc:7452
Change-Id: I1eac86f4eaff7b14820d3e4192b15c20ab6acb45
Reviewed-on: https://webrtc-review.googlesource.com/69161
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Paulina Hensman <phensman@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22820}