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

Source/core/css/CSSRuleList.h

Index: Source/core/css/CSSRuleList.h
diff --git a/Source/core/css/CSSRuleList.h b/Source/core/css/CSSRuleList.h
index 961d50db5455e0069689ea6234f5cc5a2ccf0ed1..25fe24af1fd4ddc3969e8c1d3af6c2431b5e8250 100644
--- a/Source/core/css/CSSRuleList.h
+++ b/Source/core/css/CSSRuleList.h
@@ -64,22 +64,22 @@ public:
     }
 
 #if !ENABLE(OILPAN)
-    virtual void ref() override { ++m_refCount; }
-    virtual void deref() override;
+    void ref() override { ++m_refCount; }
+    void deref() override;
 #endif
 
     WillBeHeapVector<RefPtrWillBeMember<CSSRule>>& rules() { return m_rules; }
 
-    virtual CSSStyleSheet* styleSheet() const override { return 0; }
+    CSSStyleSheet* styleSheet() const override { return 0; }
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     StaticCSSRuleList();
-    virtual ~StaticCSSRuleList();
+    ~StaticCSSRuleList() override;
 
-    virtual unsigned length() const override { return m_rules.size(); }
-    virtual CSSRule* item(unsigned index) const override { return index < m_rules.size() ? m_rules[index].get() : 0; }
+    unsigned length() const override { return m_rules.size(); }
+    CSSRule* item(unsigned index) const override { return index < m_rules.size() ? m_rules[index].get() : 0; }
 
     WillBeHeapVector<RefPtrWillBeMember<CSSRule>> m_rules;
 #if !ENABLE(OILPAN)
@@ -96,8 +96,8 @@ public:
     }
 
 #if !ENABLE(OILPAN)
-    virtual void ref() override { m_rule->ref(); }
-    virtual void deref() override { m_rule->deref(); }
+    void ref() override { m_rule->ref(); }
+    void deref() override { m_rule->deref(); }
 #endif
 
     DEFINE_INLINE_VIRTUAL_TRACE()
@@ -109,9 +109,9 @@ public:
 private:
     LiveCSSRuleList(Rule* rule) : m_rule(rule) { }
 
-    virtual unsigned length() const override { return m_rule->length(); }
-    virtual CSSRule* item(unsigned index) const override { return m_rule->item(index); }
-    virtual CSSStyleSheet* styleSheet() const override { return m_rule->parentStyleSheet(); }
+    unsigned length() const override { return m_rule->length(); }
+    CSSRule* item(unsigned index) const override { return m_rule->item(index); }
+    CSSStyleSheet* styleSheet() const override { return m_rule->parentStyleSheet(); }
 
     RawPtrWillBeMember<Rule> m_rule;
 };