Standardize usage of virtual/override/final in media/

media/audio/virtual_audio_input_stream_unittest.cc

Index: media/audio/virtual_audio_input_stream_unittest.cc
diff --git a/media/audio/virtual_audio_input_stream_unittest.cc b/media/audio/virtual_audio_input_stream_unittest.cc
index 9256f412e06c1e757ac9d329a6e0f31e897b8d48..3ff07b8f41cd05d0dd122b4940edee3b85d93c05 100644
--- a/media/audio/virtual_audio_input_stream_unittest.cc
+++ b/media/audio/virtual_audio_input_stream_unittest.cc
@@ -64,10 +64,9 @@ class TestAudioSource : public SineWaveAudioSource {
             kParams.channel_layout(), 200.0, kParams.sample_rate()),
         data_pulled_(false, false) {}
 
-  virtual ~TestAudioSource() {}
+  ~TestAudioSource() override {}
 
-  virtual int OnMoreData(AudioBus* audio_bus,
-                         uint32 total_bytes_delay) override {
+  int OnMoreData(AudioBus* audio_bus, uint32 total_bytes_delay) override {
     const int ret = SineWaveAudioSource::OnMoreData(audio_bus,
                                                     total_bytes_delay);
     data_pulled_.Signal();