Adding possibility to use encoding time when trigger underuse for frame based overuse detection.

BUG=
TEST=Added unittest.
R=asapersson@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/1885004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@4452 4adac7df-926f-26a2-2b94-8c16560cd09d
4 files changed