Configure AudioProcessing directly in agc_harness.

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}
1 file changed