Fix virtual/override/final usage in Source/core/html/.

Source/core/html/MediaController.h

Index: Source/core/html/MediaController.h
diff --git a/Source/core/html/MediaController.h b/Source/core/html/MediaController.h
index ea44deeb399119a837484573f71addcf67be2e75..07bff387f8a46d1ecf0c46672079124ecfd8756a 100644
--- a/Source/core/html/MediaController.h
+++ b/Source/core/html/MediaController.h
@@ -44,7 +44,7 @@ class MediaController final : public EventTargetWithInlineData, public RefCounte
     REFCOUNTED_EVENT_TARGET(MediaController);
 public:
     static PassRefPtrWillBeRawPtr<MediaController> create(ExecutionContext*);
-    virtual ~MediaController();
+    ~MediaController() override;
 
     void addMediaElement(HTMLMediaElement*);
     void removeMediaElement(HTMLMediaElement*);
@@ -104,8 +104,8 @@ private:
     void startTimeupdateTimer();
 
     // EventTarget
-    virtual const AtomicString& interfaceName() const override;
-    virtual ExecutionContext* executionContext() const override { return m_executionContext; }
+    const AtomicString& interfaceName() const override;
+    ExecutionContext* executionContext() const override { return m_executionContext; }
 
     friend class HTMLMediaElement;
     friend class MediaControllerEventListener;