Remove avi recorder and corresponding enable_video flags.

R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/42099004

Cr-Original-Commit-Position: refs/heads/master@{#8554}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: e8f50df6b9ebcee90ee038f7b08bbb4b525c3a05
28 files changed