This allows us to configure create-time parameters for AudioProcessing in a voice engine app and avoid the onerous SetExtraOptions. voe_cmd_test would require significant refactoring to do the same. Minor cleanups: - Use agc_manager_direct. This should allow us to remove agc_manager. - Use CHECKs rather than ASSERTs. Review URL: https://codereview.webrtc.org/1247033006 Cr-Commit-Position: refs/heads/master@{#9618}