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

Source/core/html/HTMLImageLoader.h

Index: Source/core/html/HTMLImageLoader.h
diff --git a/Source/core/html/HTMLImageLoader.h b/Source/core/html/HTMLImageLoader.h
index e2aa04319de993ce4b4771d241ac14b83a6432ee..84d4588077bbe587eb8fb1994aedca68b6f4469d 100644
--- a/Source/core/html/HTMLImageLoader.h
+++ b/Source/core/html/HTMLImageLoader.h
@@ -34,17 +34,17 @@ public:
     {
         return adoptPtrWillBeNoop(new HTMLImageLoader(element));
     }
-    virtual ~HTMLImageLoader();
+    ~HTMLImageLoader() override;
 
-    virtual void dispatchLoadEvent() override;
+    void dispatchLoadEvent() override;
 
-    virtual void notifyFinished(Resource*) override;
+    void notifyFinished(Resource*) override;
 
 private:
     Timer<HTMLImageLoader> m_loadFallbackContentTimer;
     void timerFired(Timer<HTMLImageLoader>*);
     explicit HTMLImageLoader(Element*);
-    virtual void noImageResourceToLoad() override;
+    void noImageResourceToLoad() override;
     void ensureFallbackContent();
 };