Standardize usage of virtual/override/final in media/

media/base/audio_buffer_converter.h

Index: media/base/audio_buffer_converter.h
diff --git a/media/base/audio_buffer_converter.h b/media/base/audio_buffer_converter.h
index 23db743a8bb6bfbabb12afa102e823bbc9fe2fbb..d2c4f6de0b5dff224de3ec3aaa6287ff83f7a58e 100644
--- a/media/base/audio_buffer_converter.h
+++ b/media/base/audio_buffer_converter.h
@@ -25,7 +25,7 @@ class AudioBus;
 class MEDIA_EXPORT AudioBufferConverter : public AudioConverter::InputCallback {
  public:
   explicit AudioBufferConverter(const AudioParameters& output_params);
-  virtual ~AudioBufferConverter();
+  ~AudioBufferConverter() override;
 
   void AddInput(const scoped_refptr<AudioBuffer>& buffer);
 
@@ -51,8 +51,8 @@ class MEDIA_EXPORT AudioBufferConverter : public AudioConverter::InputCallback {
 
  private:
   // Callback to provide data to the AudioConverter
-  virtual double ProvideInput(AudioBus* audio_bus,
-                              base::TimeDelta buffer_delay) override;
+  double ProvideInput(AudioBus* audio_bus,
+                      base::TimeDelta buffer_delay) override;
 
   // Reset the converter in response to a configuration change.
   void ResetConverter(const scoped_refptr<AudioBuffer>& input_buffer);