FakeVideoCaptureDevice: add support for capturing into Dma-Bufs using VGEM in CrOs

media/video/capture/fake_video_capture_device.h

Index: media/video/capture/fake_video_capture_device.h
diff --git a/media/video/capture/fake_video_capture_device.h b/media/video/capture/fake_video_capture_device.h
index f4a19f9edb9c2c6611aa8d66cc15094f905ead7f..38d9e0b2f97c2bca3dbd2a6c30cc15dc1d907c0f 100644
--- a/media/video/capture/fake_video_capture_device.h
+++ b/media/video/capture/fake_video_capture_device.h
@@ -57,6 +57,15 @@ class MEDIA_EXPORT FakeVideoCaptureDevice : public VideoCaptureDevice {
   int frame_count_;
   VideoCaptureFormat capture_format_;
 
+#if defined(OS_CHROMEOS) && defined(USE_OZONE)
+  // |client_->ReserveOutputBuffer()| might give a Buffer with null data(), in
+  // that case and for certain platforms, we can try and map the underlying
+  // Buffer::AsPlatformFile(), which is a dma-buf. This can only happen via the
+  // VGEM API. VgemWrapper encapsulates all the operations regarding it.
+  class VgemWrapper;
+  scoped_ptr<VgemWrapper> vgem_wrapper_;
+#endif
+
   // FakeVideoCaptureDevice post tasks to itself for frame construction and
   // needs to deal with asynchronous StopAndDeallocate().
   base::WeakPtrFactory<FakeVideoCaptureDevice> weak_factory_;