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

Source/core/css/StyleRuleImport.h

Index: Source/core/css/StyleRuleImport.h
diff --git a/Source/core/css/StyleRuleImport.h b/Source/core/css/StyleRuleImport.h
index dac46220ceca4c7661d5997ba28f9e0462e16755..8af71928aeef025c1bf30352ff26468f1f21382a 100644
--- a/Source/core/css/StyleRuleImport.h
+++ b/Source/core/css/StyleRuleImport.h
@@ -61,8 +61,8 @@ private:
     class ImportedStyleSheetClient final : public StyleSheetResourceClient {
     public:
         ImportedStyleSheetClient(StyleRuleImport* ownerRule) : m_ownerRule(ownerRule) { }
-        virtual ~ImportedStyleSheetClient() { }
-        virtual void setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* sheet) override
+        ~ImportedStyleSheetClient() override { }
+        void setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* sheet) override
         {
             m_ownerRule->setCSSStyleSheet(href, baseURL, charset, sheet);
         }