Break out glue for old->new Transport.

Reduces multiple inheritance and code duplication.

BUG=
R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/2239004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@4774 4adac7df-926f-26a2-2b94-8c16560cd09d
8 files changed