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}