Standardize usage of virtual/override/final in media/

media/filters/decrypting_demuxer_stream.h

Index: media/filters/decrypting_demuxer_stream.h
diff --git a/media/filters/decrypting_demuxer_stream.h b/media/filters/decrypting_demuxer_stream.h
index bad4fad06f8320bf91925ab6eee8ed98b38ed244..09bf97aaf3618c2a0c053c543535c1c050e423e9 100644
--- a/media/filters/decrypting_demuxer_stream.h
+++ b/media/filters/decrypting_demuxer_stream.h
@@ -33,7 +33,7 @@ class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
       const SetDecryptorReadyCB& set_decryptor_ready_cb);
 
   // Cancels all pending operations immediately and fires all pending callbacks.
-  virtual ~DecryptingDemuxerStream();
+  ~DecryptingDemuxerStream() override;
 
   void Initialize(DemuxerStream* stream,
                   const PipelineStatusCB& status_cb);
@@ -45,13 +45,13 @@ class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
   void Reset(const base::Closure& closure);
 
   // 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 void EnableBitstreamConverter() 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;
+  void EnableBitstreamConverter() override;
+  bool SupportsConfigChanges() override;
+  VideoRotation video_rotation() override;
 
  private:
   // For a detailed state diagram please see this link: http://goo.gl/8jAok