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

Source/core/timing/PerformanceMeasure.h

Index: Source/core/timing/PerformanceMeasure.h
diff --git a/Source/core/timing/PerformanceMeasure.h b/Source/core/timing/PerformanceMeasure.h
index d384d77be4df90792870324986d62ee3a9202b48..0fcbad0f63a046d7b8899a08b655d9ec11c740fa 100644
--- a/Source/core/timing/PerformanceMeasure.h
+++ b/Source/core/timing/PerformanceMeasure.h
@@ -41,7 +41,7 @@ public:
         return new PerformanceMeasure(name, startTime, endTime);
     }
 
-    virtual bool isMeasure() override { return true; }
+    bool isMeasure() override { return true; }
 
     DEFINE_INLINE_VIRTUAL_TRACE()
     {
@@ -51,7 +51,7 @@ public:
 private:
     PerformanceMeasure(const String& name, double startTime, double endTime)
         : PerformanceEntry(name, "measure", startTime, endTime) { }
-    virtual ~PerformanceMeasure() { }
+    ~PerformanceMeasure() override { }
 };
 
 } // namespace blink