Wire up external encoders.

R=pthatcher@webrtc.org
BUG=1788

Review URL: https://webrtc-codereview.appspot.com/30649005

git-svn-id: http://webrtc.googlecode.com/svn/trunk/talk@7440 4adac7df-926f-26a2-2b94-8c16560cd09d
5 files changed