Theil and Sen's estimator essentially looks at the line through every pair of points and selects the median slope. This is robust to corruption of up to 29% of the data points. Wire up new estimator to field trial experiment. Add unit and integration tests. Results are promising. BUG=webrtc:6728 Review-Url: https://codereview.webrtc.org/2512693002 Cr-Commit-Position: refs/heads/master@{#15508}