Update {virtual,override} to follow C++11 style in content/common/gpu/media

content/common/gpu/media/v4l2_slice_video_decode_accelerator.h

Index: content/common/gpu/media/v4l2_slice_video_decode_accelerator.h
diff --git a/content/common/gpu/media/v4l2_slice_video_decode_accelerator.h b/content/common/gpu/media/v4l2_slice_video_decode_accelerator.h
index 832e1e7e667f9904c12bbecbdad4b1ab03130667..1a8644ded2213600541387109412582bae1efef1 100644
--- a/content/common/gpu/media/v4l2_slice_video_decode_accelerator.h
+++ b/content/common/gpu/media/v4l2_slice_video_decode_accelerator.h
@@ -39,7 +39,7 @@ class CONTENT_EXPORT V4L2SliceVideoDecodeAccelerator
       const base::WeakPtr<Client>& io_client_,
       const base::Callback<bool(void)>& make_context_current,
       const scoped_refptr<base::MessageLoopProxy>& io_message_loop_proxy);
-  virtual ~V4L2SliceVideoDecodeAccelerator() override;
+  ~V4L2SliceVideoDecodeAccelerator() override;
 
   // media::VideoDecodeAccelerator implementation.
   bool Initialize(media::VideoCodecProfile profile,