Fix virtual/override/final usage in Source/core/html/.

Source/core/html/HTMLSourceElement.cpp

Index: Source/core/html/HTMLSourceElement.cpp
diff --git a/Source/core/html/HTMLSourceElement.cpp b/Source/core/html/HTMLSourceElement.cpp
index f1138b2a7e84f4f35ceb9cd53cd4dd432c3150fa..95fcfe13d6b14ac7b69d05dde7ca64a9cdadd57a 100644
--- a/Source/core/html/HTMLSourceElement.cpp
+++ b/Source/core/html/HTMLSourceElement.cpp
@@ -50,7 +50,7 @@ static SourceEventSender& sourceErrorEventSender()
 class HTMLSourceElement::Listener final : public MediaQueryListListener {
 public:
     explicit Listener(HTMLSourceElement* element) : m_element(element) { }
-    virtual void notifyMediaQueryChanged() override
+    void notifyMediaQueryChanged() override
     {
         if (m_element)
             m_element->notifyMediaQueryChanged();