Update CSS classes to use OVERRIDE / FINAL when needed

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 8af664e24382c4900408245c0404a41b243b2082..687ca8ad2c342984a68193c892f66d35dc7b296c 100644
--- a/Source/core/css/StyleRuleImport.h
+++ b/Source/core/css/StyleRuleImport.h
@@ -54,11 +54,11 @@ public:
 private:
     // NOTE: We put the StyleSheetResourceClient in a member instead of inheriting from it
     // to avoid adding a vptr to StyleRuleImport.
-    class ImportedStyleSheetClient : public StyleSheetResourceClient {
+    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)
+        virtual void setCSSStyleSheet(const String& href, const KURL& baseURL, const String& charset, const CSSStyleSheetResource* sheet) OVERRIDE
         {
             m_ownerRule->setCSSStyleSheet(href, baseURL, charset, sheet);
         }