Adding back platform specific renderer to video loopback test.

BUG=3039
TEST=locally on Mac and Win, video_loopback test
R=pbos@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/10689004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6339 4adac7df-926f-26a2-2b94-8c16560cd09d
8 files changed