The purpose for the xvfb mode is to be able to run tests on the windowless environment on the Chromebot. Given the right input video, we can then write a relatively simple algorithm to analyze the screenshots and thereby conclude that video is playing.
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Review URL: https://webrtc-codereview.appspot.com/447004
git-svn-id: http://webrtc.googlecode.com/svn/trunk@1890 4adac7df-926f-26a2-2b94-8c16560cd09d