Remove DeviceManager and DeviceInfo.

BUG=webrtc:5615, webrtc:5620

Review URL: https://codereview.webrtc.org/1715883002

Cr-Original-Commit-Position: refs/heads/master@{#12020}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 8ad582d83ffb935ba06b2474d1ec1ff3650ac376
31 files changed