Revert of Delete empty API files and cleaned up includes.

webrtc/api/videotrack.h

 /*
  *  Copyright 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_API_VIDEOTRACK_H_
 #define WEBRTC_API_VIDEOTRACK_H_
 
 #include <string>
 #include <vector>
 
 #include "webrtc/api/mediastreamtrack.h"
+#include "webrtc/api/videosourceinterface.h"
+#include "webrtc/api/videotrackrenderers.h"
 #include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/media/base/videosourcebase.h"
 
 namespace webrtc {
 
 class VideoTrack : public MediaStreamTrack<VideoTrackInterface>,
                    public rtc::VideoSourceBase {
  public:
   static rtc::scoped_refptr<VideoTrack> Create(
@@ skipping 15 matching lines @@
   ~VideoTrack();
 
  private:
   rtc::ThreadChecker thread_checker_;
   rtc::scoped_refptr<VideoTrackSourceInterface> video_source_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_VIDEOTRACK_H_