[Mojo Video Capture] Add test coverage for accelerated jpeg decoding

media/capture/video/video_capture_device_client.h

Index: media/capture/video/video_capture_device_client.h
diff --git a/media/capture/video/video_capture_device_client.h b/media/capture/video/video_capture_device_client.h
index a1b298fe81e02769cc1d70f644823b6d7f80f6a1..c6fddcbdf1e9c39addcd381fac52540fd6c41c40 100644
--- a/media/capture/video/video_capture_device_client.h
+++ b/media/capture/video/video_capture_device_client.h
@@ -85,6 +85,8 @@ class CAPTURE_EXPORT VideoCaptureDeviceClient
   double GetBufferPoolUtilization() const override;
 
  private:
+  void OnUsingExternalJpegDecoder();
+
   void InitializeI420PlanePointers(const gfx::Size& dimensions,
                                    uint8_t* const data,
                                    uint8_t** y_plane_data,
@@ -108,6 +110,7 @@ class CAPTURE_EXPORT VideoCaptureDeviceClient
 
   // Whether |external_jpeg_decoder_| has been initialized.
   bool external_jpeg_decoder_initialized_;
+  bool using_external_jpeg_decoder_;

[mcasas, 2017/03/08 01:33:17]

What about removing OnUsingExternalJpegDecoder()
and |using_external_jpeg_decoder_|, instead having
a base::CallbackOnce, you bind it using BindOnce(), 
in the ctor and with base::Unretained(receiver_) and 
VideoFrameReceiver::OnStartedUsingGpuDecode().
Test before Run()ing it as you'd do with a unique_ptr.

[chfremer, 2017/03/08 18:58:08]

Done.

 
   // The pool of shared-memory buffers used for capturing.
   const scoped_refptr<VideoCaptureBufferPool> buffer_pool_;