Caused when recyclingframes until the next key frame to regain frame buffers when the jitter buffer is full. BUG=http://code.google.com/p/webrtc/issues/detail?id=225 TEST= Review URL: http://webrtc-codereview.appspot.com/350005 git-svn-id: http://webrtc.googlecode.com/svn/trunk@1390 4adac7df-926f-26a2-2b94-8c16560cd09d