Moved VideoSourceInterface to MediaStreamInterface.h Renamed VideoSourceTest to VideoCapturerTrackSourceTest Renamed VideoSource to VideoCaptureTrackSource and cl lint and cl format. BUG=webrtc:5426 TBR=pthatcher@webrtc.org Review URL: https://codereview.webrtc.org/1770003002 . Cr-Commit-Position: refs/heads/master@{#11893}