Standardize usage of virtual/override/final in media/

media/mojo/services/mojo_demuxer_stream_impl.h

Index: media/mojo/services/mojo_demuxer_stream_impl.h
diff --git a/media/mojo/services/mojo_demuxer_stream_impl.h b/media/mojo/services/mojo_demuxer_stream_impl.h
index 85b0c17547152814531d86cf221a444b8356714f..46333e4c80c6c11c1cea18da0d5961d326eaec33 100644
--- a/media/mojo/services/mojo_demuxer_stream_impl.h
+++ b/media/mojo/services/mojo_demuxer_stream_impl.h
@@ -21,15 +21,15 @@ class MojoDemuxerStreamImpl : public mojo::InterfaceImpl<mojo::DemuxerStream> {
   // |stream| is the underlying DemuxerStream we are proxying for.
   // Note: |this| does not take ownership of |stream|.
   explicit MojoDemuxerStreamImpl(media::DemuxerStream* stream);
-  virtual ~MojoDemuxerStreamImpl();
+  ~MojoDemuxerStreamImpl() override;
 
   // mojo::DemuxerStream implementation.
-  virtual void Read(const mojo::Callback<
-      void(mojo::DemuxerStream::Status, mojo::MediaDecoderBufferPtr)>& callback)
+  void Read(const mojo::Callback<void(mojo::DemuxerStream::Status,
+                                      mojo::MediaDecoderBufferPtr)>& callback)
       override;
 
   // mojo::InterfaceImpl overrides.
-  virtual void OnConnectionEstablished() override;
+  void OnConnectionEstablished() override;
 
  private:
   // |callback| is the callback that was passed to the initiating Read()