Standardize usage of virtual/override/final in content/

content/test/test_media_stream_renderer_factory.h

Index: content/test/test_media_stream_renderer_factory.h
diff --git a/content/test/test_media_stream_renderer_factory.h b/content/test/test_media_stream_renderer_factory.h
index 042c90269b2c14c9559d6892c897b4d7f0e21e14..398be0738176d7a8dc61b1e89822d9a193912e72 100644
--- a/content/test/test_media_stream_renderer_factory.h
+++ b/content/test/test_media_stream_renderer_factory.h
@@ -16,15 +16,15 @@ namespace content {
 class TestMediaStreamRendererFactory : public MediaStreamRendererFactory {
  public:
   TestMediaStreamRendererFactory();
-  virtual ~TestMediaStreamRendererFactory();
+  ~TestMediaStreamRendererFactory() override;
 
   // MediaStreamRendererFactory implementation.
-  virtual scoped_refptr<VideoFrameProvider> GetVideoFrameProvider(
+  scoped_refptr<VideoFrameProvider> GetVideoFrameProvider(
       const GURL& url,
       const base::Closure& error_cb,
       const VideoFrameProvider::RepaintCB& repaint_cb) override;
 
-  virtual scoped_refptr<MediaStreamAudioRenderer> GetAudioRenderer(
+  scoped_refptr<MediaStreamAudioRenderer> GetAudioRenderer(
       const GURL& url,
       int render_view_id,
       int render_frame_id) override;