The minimum bitrate can now be configured from WrappingBitrateEstimator. BUG=2698 R=stefan@webrtc.org Review URL: https://webrtc-codereview.appspot.com/5699004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@5279 4adac7df-926f-26a2-2b94-8c16560cd09d