Standardize usage of virtual/override/final in media/

media/filters/fake_demuxer_stream.h

Index: media/filters/fake_demuxer_stream.h
diff --git a/media/filters/fake_demuxer_stream.h b/media/filters/fake_demuxer_stream.h
index fbb615104c8a1f9db2f1fa8b671748e40987f0d7..fd651dc28ad30f56e563de229461395684efef30 100644
--- a/media/filters/fake_demuxer_stream.h
+++ b/media/filters/fake_demuxer_stream.h
@@ -25,15 +25,15 @@ class FakeDemuxerStream : public DemuxerStream {
   FakeDemuxerStream(int num_configs,
                     int num_buffers_in_one_config,
                     bool is_encrypted);
-  virtual ~FakeDemuxerStream();
+  ~FakeDemuxerStream() override;
 
   // DemuxerStream implementation.
-  virtual void Read(const ReadCB& read_cb) override;
-  virtual AudioDecoderConfig audio_decoder_config() override;
-  virtual VideoDecoderConfig video_decoder_config() override;
-  virtual Type type() override;
-  virtual bool SupportsConfigChanges() override;
-  virtual VideoRotation video_rotation() override;
+  void Read(const ReadCB& read_cb) override;
+  AudioDecoderConfig audio_decoder_config() override;
+  VideoDecoderConfig video_decoder_config() override;
+  Type type() override;
+  bool SupportsConfigChanges() override;
+  VideoRotation video_rotation() override;
 
   void Initialize();