* First do all frame processing, then do all rate control statistics calculations. This means that we only need to synchronize once. * Run the VideoProcessor on a task queue, thus supporting Android HW codecs. * Add some unit tests for the VideoProcessor. BUG=webrtc:6634 Review-Url: https://codereview.webrtc.org/2997283002 Cr-Commit-Position: refs/heads/master@{#19604}