Fix virtual/override/final usage in Source/core/{animation,css,style}/.

Source/core/css/CSSMediaRule.h

Index: Source/core/css/CSSMediaRule.h
diff --git a/Source/core/css/CSSMediaRule.h b/Source/core/css/CSSMediaRule.h
index 93b61da16c6179fb98d15ad8afc978fd64cc7789..b0f75b05c11932ae437932c43a1c360c0fb3f1bf 100644
--- a/Source/core/css/CSSMediaRule.h
+++ b/Source/core/css/CSSMediaRule.h
@@ -38,10 +38,10 @@ public:
         return adoptRefWillBeNoop(new CSSMediaRule(rule, sheet));
     }
 
-    virtual ~CSSMediaRule();
+    ~CSSMediaRule() override;
 
-    virtual void reattach(StyleRuleBase*) override;
-    virtual String cssText() const override;
+    void reattach(StyleRuleBase*) override;
+    String cssText() const override;
 
     MediaList* media() const;
 
@@ -50,7 +50,7 @@ public:
 private:
     CSSMediaRule(StyleRuleMedia*, CSSStyleSheet*);
 
-    virtual CSSRule::Type type() const override { return MEDIA_RULE; }
+    CSSRule::Type type() const override { return MEDIA_RULE; }
 
     MediaQuerySet* mediaQueries() const;