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

Source/core/events/CustomEvent.h

Index: Source/core/events/CustomEvent.h
diff --git a/Source/core/events/CustomEvent.h b/Source/core/events/CustomEvent.h
index 2d5dfe1ec35654a7968b80e5cf1d03ab16de1008..5fa94c952c946bfc35f10707090e475fa4782103 100644
--- a/Source/core/events/CustomEvent.h
+++ b/Source/core/events/CustomEvent.h
@@ -37,7 +37,7 @@ class SerializedScriptValue;
 class CORE_EXPORT CustomEvent final : public Event {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    virtual ~CustomEvent();
+    ~CustomEvent() override;
 
     static PassRefPtrWillBeRawPtr<CustomEvent> create()
     {
@@ -51,7 +51,7 @@ public:
 
     void initCustomEvent(const AtomicString& type, bool canBubble, bool cancelable, PassRefPtr<SerializedScriptValue>);
 
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     SerializedScriptValue* serializedDetail() { return m_serializedDetail.get(); }