i420_video_frame.h was removed in https://webrtc-codereview.appspot.com/46819004/ but common_video.gyp was not updated with this change. BUG=N/A TBR=tfarina@chromium.org Review URL: https://webrtc-codereview.appspot.com/51569004 Cr-Commit-Position: refs/heads/master@{#8974}