Fix virtual/override/final usage in Source/modules/.

Source/modules/webaudio/MediaElementAudioSourceNode.h

Index: Source/modules/webaudio/MediaElementAudioSourceNode.h
diff --git a/Source/modules/webaudio/MediaElementAudioSourceNode.h b/Source/modules/webaudio/MediaElementAudioSourceNode.h
index 055be41ebf67b3dff287e592c1f8bd3d6162df13..fc5322306091f1e666564716fc0dd4ab5cb5436f 100644
--- a/Source/modules/webaudio/MediaElementAudioSourceNode.h
+++ b/Source/modules/webaudio/MediaElementAudioSourceNode.h
@@ -42,13 +42,13 @@ class HTMLMediaElement;
 class MediaElementAudioSourceHandler final : public AudioHandler {
 public:
     static PassRefPtr<MediaElementAudioSourceHandler> create(AudioNode&, HTMLMediaElement&);
-    virtual ~MediaElementAudioSourceHandler();
+    ~MediaElementAudioSourceHandler() override;
 
     HTMLMediaElement* mediaElement() { return m_mediaElement.get(); }
 
     // AudioHandler
-    virtual void dispose() override;
-    virtual void process(size_t framesToProcess) override;
+    void dispose() override;
+    void process(size_t framesToProcess) override;
 
     // Helpers for AudioSourceProviderClient implementation of
     // MediaElementAudioSourceNode.
@@ -60,7 +60,7 @@ public:
 private:
     MediaElementAudioSourceHandler(AudioNode&, HTMLMediaElement&);
     // As an audio source, we will never propagate silence.
-    virtual bool propagatesSilence() const override { return false; }
+    bool propagatesSilence() const override { return false; }
 
     // Must be called only on the audio thread.
     bool passesCORSAccessCheck();