This fixes an issue where the user doesn't know which channels are "active" and therefore can't properly sum the estimates for all channels. R=pbos@webrtc.org Review URL: https://webrtc-codereview.appspot.com/12469004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@6041 4adac7df-926f-26a2-2b94-8c16560cd09d