This removes call of av_register_all(), which is deprecated, and
related code.
Bug: webrtc:9352
Change-Id: Ib7de5931c900eaf1023ecf3046f560feaaeec8ef
Reviewed-on: https://webrtc-review.googlesource.com/85347
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Commit-Queue: Sergey Silkin <ssilkin@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23743}