Modify the simulcast encoder factory adapter to allow external encoder factories that support more than one codec.

Only VP8 encoders will be wrapped in the simulcast adapter; other codec types will be created directly with the real encoder factory and cleaned up appropriately.

BUG=
R=pbos@webrtc.org, pthatcher@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/40169004

Cr-Commit-Position: refs/heads/master@{#8623}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8623 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed