Add new view that renders local video using AVCaptureLayerPreview.

BUG=

Review URL: https://codereview.webrtc.org/1497393002

Cr-Original-Commit-Position: refs/heads/master@{#10940}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: edd8fefa9b31f903eefe1e9fcabb09a5d6fc1ad1
10 files changed