Standardize usage of virtual/override/final in media/

media/blink/video_frame_compositor.h

Index: media/blink/video_frame_compositor.h
diff --git a/media/blink/video_frame_compositor.h b/media/blink/video_frame_compositor.h
index a76c122f6a252fae3ba6c2a89a868743dc084193..f8bdd1e63fc63bb3dc901d0c0979fba7083249ea 100644
--- a/media/blink/video_frame_compositor.h
+++ b/media/blink/video_frame_compositor.h
@@ -40,14 +40,13 @@ class MEDIA_EXPORT VideoFrameCompositor
   VideoFrameCompositor(
       const base::Callback<void(gfx::Size)>& natural_size_changed_cb,
       const base::Callback<void(bool)>& opacity_changed_cb);
-  virtual ~VideoFrameCompositor();
+  ~VideoFrameCompositor() override;
 
   // cc::VideoFrameProvider implementation.
-  virtual void SetVideoFrameProviderClient(
+  void SetVideoFrameProviderClient(
       cc::VideoFrameProvider::Client* client) override;
-  virtual scoped_refptr<VideoFrame> GetCurrentFrame() override;
-  virtual void PutCurrentFrame(
-      const scoped_refptr<VideoFrame>& frame) override;
+  scoped_refptr<VideoFrame> GetCurrentFrame() override;
+  void PutCurrentFrame(const scoped_refptr<VideoFrame>& frame) override;
 
   // Updates the current frame and notifies the compositor.
   void UpdateCurrentFrame(const scoped_refptr<VideoFrame>& frame);