Add configuration for ability to use the encode usage measure for triggering overuse/underuse.

BUG=1577
R=mflodman@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/10509004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5767 4adac7df-926f-26a2-2b94-8c16560cd09d
3 files changed