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

Source/core/events/TransitionEvent.h

Index: Source/core/events/TransitionEvent.h
diff --git a/Source/core/events/TransitionEvent.h b/Source/core/events/TransitionEvent.h
index 33d3acd9108ce621563749dc46c48ffc27e42378..b7527df7f759713ab4086cb21858d32f0403c1ef 100644
--- a/Source/core/events/TransitionEvent.h
+++ b/Source/core/events/TransitionEvent.h
@@ -48,13 +48,13 @@ public:
         return adoptRefWillBeNoop(new TransitionEvent(type, initializer));
     }
 
-    virtual ~TransitionEvent();
+    ~TransitionEvent() override;
 
     const String& propertyName() const;
     double elapsedTime() const;
     const String& pseudoElement() const;
 
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     DECLARE_VIRTUAL_TRACE();