Standardize usage of virtual/override/final specifiers.

media/audio/pulse/pulse_input.h

Index: media/audio/pulse/pulse_input.h
diff --git a/media/audio/pulse/pulse_input.h b/media/audio/pulse/pulse_input.h
index dd42b31489ef0f1cc4e25082eb75ecc556e336a4..e3316cd7c531d0c7ca083b4a2725794f0f184f84 100644
--- a/media/audio/pulse/pulse_input.h
+++ b/media/audio/pulse/pulse_input.h
@@ -27,17 +27,17 @@ class PulseAudioInputStream : public AgcAudioStream<AudioInputStream> {
                         pa_threaded_mainloop* mainloop,
                         pa_context* context);
 
-  virtual ~PulseAudioInputStream();
+  ~PulseAudioInputStream() override;
 
   // Implementation of AudioInputStream.
-  virtual bool Open() override;
-  virtual void Start(AudioInputCallback* callback) override;
-  virtual void Stop() override;
-  virtual void Close() override;
-  virtual double GetMaxVolume() override;
-  virtual void SetVolume(double volume) override;
-  virtual double GetVolume() override;
-  virtual bool IsMuted() override;
+  bool Open() override;
+  void Start(AudioInputCallback* callback) override;
+  void Stop() override;
+  void Close() override;
+  double GetMaxVolume() override;
+  void SetVolume(double volume) override;
+  double GetVolume() override;
+  bool IsMuted() override;
 
  private:
   // PulseAudio Callbacks.