Decouple capture timestamp and reference time

media/capture/video/file_video_capture_device.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_
 #define MEDIA_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 63 matching lines @@
   // |capture_thread_| is used for internal operations via posting tasks to it.
   // It is active between OnAllocateAndStart() and OnStopAndDeAllocate().
   base::Thread capture_thread_;
   // The following members belong to |capture_thread_|.
   std::unique_ptr<VideoCaptureDevice::Client> client_;
   const base::FilePath file_path_;
   std::unique_ptr<VideoFileParser> file_parser_;
   VideoCaptureFormat capture_format_;
   // Target time for the next frame.
   base::TimeTicks next_frame_time_;
+  // The system time when we receive the first frame.
+  base::TimeTicks first_ref_time_;
 
   DISALLOW_COPY_AND_ASSIGN(FileVideoCaptureDevice);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_FILE_VIDEO_CAPTURE_DEVICE_H_