New VideoEngine API implementation on top of old one, first steps.

BUG=1668
R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1360004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4044 4adac7df-926f-26a2-2b94-8c16560cd09d
26 files changed