Decouple capture timestamp and reference time

media/capture/video/file_video_capture_device.cc

Index: media/capture/video/file_video_capture_device.cc
diff --git a/media/capture/video/file_video_capture_device.cc b/media/capture/video/file_video_capture_device.cc
index d06741e705a04d2b82c7a9519ec70b383089fcfc..be5a557da4e4d50001921e46813f2ab592b9f638 100644
--- a/media/capture/video/file_video_capture_device.cc
+++ b/media/capture/video/file_video_capture_device.cc
@@ -366,8 +366,10 @@ void FileVideoCaptureDevice::OnCaptureTask() {
   DCHECK(frame_size);
   CHECK(frame_ptr);
   const base::TimeTicks current_time = base::TimeTicks::Now();
+  if (first_ref_time_.is_null())
+    first_ref_time_ = current_time;
   client_->OnIncomingCapturedData(frame_ptr, frame_size, capture_format_, 0,
-                                  current_time);
+                                  current_time, current_time - first_ref_time_);
   // Reschedule next CaptureTask.
   const base::TimeDelta frame_interval =
       base::TimeDelta::FromMicroseconds(1E6 / capture_format_.frame_rate);