This is a reland of 51698aefd4925f2dfa0310a321f836d433fa9258
Original change's description:
> Put internal video codec factories into separate target
>
> The purpose is to start splitting out the dependencies to the built-in
> SW video codecs, so that clients can decide to not depend on them and
> get a reduction in binary size.
>
> Replaces https://webrtc-review.googlesource.com/c/src/+/29101
>
> Bug: webrtc:7925
> Change-Id: I46b95aaf42ead70ba78776de60600b8a66a1fe0c
> Reviewed-on: https://webrtc-review.googlesource.com/33420
> Commit-Queue: Anders Carlsson <andersc@webrtc.org>
> Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#21381}
Bug: webrtc:7925
Change-Id: I105287fd41ec3ee5bd964b94efcc9c7b3ecdb842
Reviewed-on: https://webrtc-review.googlesource.com/35261
Reviewed-by: Magnus Jedvert <magjed@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#21389}