These changes are currently not used in webrtc/ but helps in using the delay estimator. * The last_delay_quality() is updated with respect to robust_validation and changed to return float. * Tests are updated wtih respect to above. * Adds the possibility to make a soft reset based on external circumstances like a known delay shift has been made. * The soft reset change the lookahead dynamically. An API to ask for current lookahead has been added as well. BUG=N/A TESTED=trybots, modules_unittest R=aluebs@webrtc.org, andrew@webrtc.org Review URL: https://webrtc-codereview.appspot.com/10409004 git-svn-id: http://webrtc.googlecode.com/svn/trunk@5761 4adac7df-926f-26a2-2b94-8c16560cd09d