Clean up virtual functions in css/

Source/core/css/CSSStyleRule.h

Index: Source/core/css/CSSStyleRule.h
diff --git a/Source/core/css/CSSStyleRule.h b/Source/core/css/CSSStyleRule.h
index 86f855218fd19f96c4887fa1f9dbc7e007dc1099..cdf7a8303fcef61d34612d2ab14e39d3fc9d4bcd 100644
--- a/Source/core/css/CSSStyleRule.h
+++ b/Source/core/css/CSSStyleRule.h
@@ -41,7 +41,6 @@ public:
 
     virtual ~CSSStyleRule();
 
-    virtual CSSRule::Type type() const override { return STYLE_RULE; }
     virtual String cssText() const override;
     virtual void reattach(StyleRuleBase*) override;
 
@@ -58,6 +57,8 @@ public:
 private:
     CSSStyleRule(StyleRule*, CSSStyleSheet*);
 
+    virtual CSSRule::Type type() const override { return STYLE_RULE; }
+
     String generateSelectorText() const;
 
     RefPtrWillBeMember<StyleRule> m_styleRule;