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

Source/core/html/track/TextTrackContainer.h

Index: Source/core/html/track/TextTrackContainer.h
diff --git a/Source/core/html/track/TextTrackContainer.h b/Source/core/html/track/TextTrackContainer.h
index 2658124a0ed766e84e4bbb74368bafe2e00a6595..29d9b4399338db61f83bcce02ecea9a580767275 100644
--- a/Source/core/html/track/TextTrackContainer.h
+++ b/Source/core/html/track/TextTrackContainer.h
@@ -52,9 +52,9 @@ public:
 private:
     TextTrackContainer(Document&);
 
-    virtual bool isTextTrackContainer() const override { return true; }
+    bool isTextTrackContainer() const override { return true; }
 
-    virtual LayoutObject* createLayoutObject(const ComputedStyle&) override;
+    LayoutObject* createLayoutObject(const ComputedStyle&) override;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(TextTrackContainer, isTextTrackContainer());