Trigger a PLI if the duration of non-decodable frames exceeds a threshold.

BUG=1663
R=mikhal@webrtc.org, ronghuawu@chromium.org

Review URL: https://webrtc-codereview.appspot.com/1359004

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3975 4adac7df-926f-26a2-2b94-8c16560cd09d
17 files changed