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

Source/core/events/BeforeTextInsertedEvent.h

Index: Source/core/events/BeforeTextInsertedEvent.h
diff --git a/Source/core/events/BeforeTextInsertedEvent.h b/Source/core/events/BeforeTextInsertedEvent.h
index fa074bebaa16539f9056a77daa868a0bf0b496ff..4490adcf5bf8c54d548ea341bc5326d2e93d4a55 100644
--- a/Source/core/events/BeforeTextInsertedEvent.h
+++ b/Source/core/events/BeforeTextInsertedEvent.h
@@ -32,15 +32,15 @@ namespace blink {
 
 class BeforeTextInsertedEvent final : public Event {
 public:
-    virtual ~BeforeTextInsertedEvent();
+    ~BeforeTextInsertedEvent() override;
 
     static PassRefPtrWillBeRawPtr<BeforeTextInsertedEvent> create(const String& text)
     {
         return adoptRefWillBeNoop(new BeforeTextInsertedEvent(text));
     }
 
-    virtual const AtomicString& interfaceName() const override;
-    virtual bool isBeforeTextInsertedEvent() const override { return true; }
+    const AtomicString& interfaceName() const override;
+    bool isBeforeTextInsertedEvent() const override { return true; }
 
     const String& text() const { return m_text; }
     void setText(const String& s) { m_text = s; }