Made it possible to render custom call output to file.

This is to enable quality tests using the custom call.

BUG=
TESTED=locally

Review URL: https://webrtc-codereview.appspot.com/1093005

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3483 4adac7df-926f-26a2-2b94-8c16560cd09d
1 file changed