Fix virtual/override/final usage in the rest of Source/core/.

Source/core/timing/PerformanceCompositeTiming.h

Index: Source/core/timing/PerformanceCompositeTiming.h
diff --git a/Source/core/timing/PerformanceCompositeTiming.h b/Source/core/timing/PerformanceCompositeTiming.h
index 1b4f8934c62123e714309c908041d91b49c76e5f..976273518c1d4b9758df83c7de0fef1dd159bfc9 100644
--- a/Source/core/timing/PerformanceCompositeTiming.h
+++ b/Source/core/timing/PerformanceCompositeTiming.h
@@ -51,13 +51,13 @@ public:
 
     unsigned sourceFrame() const;
 
-    virtual bool isComposite() override { return true; }
+    bool isComposite() override { return true; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     PerformanceCompositeTiming(Document* requestingDocument, unsigned sourceFrame, double startTime);
-    virtual ~PerformanceCompositeTiming();
+    ~PerformanceCompositeTiming() override;
 
     unsigned m_sourceFrame;
     RefPtrWillBeMember<Document> m_requestingDocument;