Switch to using new ACM methods for encoder management

BUG=webrtc:5028

Review URL: https://codereview.webrtc.org/1677013002

Cr-Original-Commit-Position: refs/heads/master@{#12267}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: c8d071e4e074934ef8346fc91ad4f24ae333afee
8 files changed