Make V4L2CaptureDelegate non-ref-counted

media/capture/video/linux/video_capture_device_linux.h

Index: media/capture/video/linux/video_capture_device_linux.h
diff --git a/media/capture/video/linux/video_capture_device_linux.h b/media/capture/video/linux/video_capture_device_linux.h
index f8368009588c6dd7401912e524a9ef0d80767606..f79b247914c0e09df7be99ba0471e6baa19b36e4 100644
--- a/media/capture/video/linux/video_capture_device_linux.h
+++ b/media/capture/video/linux/video_capture_device_linux.h
@@ -55,7 +55,7 @@ class VideoCaptureDeviceLinux : public VideoCaptureDevice {
   // Internal delegate doing the actual capture setting, buffer allocation and
   // circulation with the V4L2 API. Created and deleted in the thread where
   // VideoCaptureDeviceLinux lives but otherwise operating on |v4l2_thread_|.
-  scoped_refptr<V4L2CaptureDelegate> capture_impl_;
+  std::unique_ptr<V4L2CaptureDelegate> capture_impl_;
 
   // Photo-related requests waiting for |v4l2_thread_| to be active.
   std::list<base::Closure> photo_requests_queue_;