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

Source/core/html/shadow/MediaControlElementTypes.h

Index: Source/core/html/shadow/MediaControlElementTypes.h
diff --git a/Source/core/html/shadow/MediaControlElementTypes.h b/Source/core/html/shadow/MediaControlElementTypes.h
index e80b9eb68a13e6f157ca1e37dea2dd5fca56673a..09ad25fe82421f4fb91c91483cb4f623a241aef4 100644
--- a/Source/core/html/shadow/MediaControlElementTypes.h
+++ b/Source/core/html/shadow/MediaControlElementTypes.h
@@ -108,7 +108,7 @@ protected:
     MediaControlDivElement(MediaControls&, MediaControlElementType);
 
 private:
-    virtual bool isMediaControlElement() const override final { return true; }
+    bool isMediaControlElement() const final { return true; }
 };
 
 // ----------------------------
@@ -123,8 +123,8 @@ protected:
 
 private:
     virtual void updateDisplayType() { }
-    virtual bool isMediaControlElement() const override final { return true; }
-    virtual bool isMouseFocusable() const override;
+    bool isMediaControlElement() const final { return true; }
+    bool isMouseFocusable() const override;
 };
 
 // ----------------------------