Decouple capture timestamp and reference time

media/capture/video/fake_video_capture_device.h

 // Copyright (c) 2012 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.
 
 // Implementation of a fake VideoCaptureDevice class. Used for testing other
 // video capture classes when no real hardware is available.
 
 #ifndef MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_
 #define MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_
 
@@ skipping 45 matching lines @@
 
   std::unique_ptr<VideoCaptureDevice::Client> client_;
   // |fake_frame_| is used for capturing on Own Buffers.
   std::unique_ptr<uint8_t[]> fake_frame_;
   // Time when the next beep occurs.
   base::TimeDelta beep_time_;
   // Time since the fake video started rendering frames.
   base::TimeDelta elapsed_time_;
   VideoCaptureFormat capture_format_;
 
+  // The system time when we receive the first frame.
+  base::TimeTicks first_ref_time_;
   // FakeVideoCaptureDevice post tasks to itself for frame construction and
   // needs to deal with asynchronous StopAndDeallocate().
   base::WeakPtrFactory<FakeVideoCaptureDevice> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeVideoCaptureDevice);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_VIDEO_CAPTURE_FAKE_VIDEO_CAPTURE_DEVICE_H_