Add histograms stats for sent/received fraction loss for a stream:
- "WebRTC.Video.SentPacketsLostInPercent"
- "WebRTC.Video.ReceivedPacketsLostInPercent"

BUG=crbug/419657
R=mflodman@webrtc.org, stefan@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/37419004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@8020 4adac7df-926f-26a2-2b94-8c16560cd09d
7 files changed