Update more core classes to use OVERRIDE / FINAL when needed

Source/core/css/CSSStyleSheet.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2012 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 23 matching lines @@
 #include "core/dom/Document.h"
 #include "core/dom/ExceptionCode.h"
 #include "core/dom/Node.h"
 #include "core/frame/UseCounter.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "platform/weborigin/SecurityOrigin.h"
 #include "wtf/text/StringBuilder.h"
 
 namespace WebCore {
 
-class StyleSheetCSSRuleList : public CSSRuleList {
+class StyleSheetCSSRuleList FINAL : public CSSRuleList {
 public:
     StyleSheetCSSRuleList(CSSStyleSheet* sheet) : m_styleSheet(sheet) { }
 
 private:
-    virtual void ref() { m_styleSheet->ref(); }
-    virtual void deref() { m_styleSheet->deref(); }
+    virtual void ref() OVERRIDE { m_styleSheet->ref(); }
+    virtual void deref() OVERRIDE { m_styleSheet->deref(); }
 
-    virtual unsigned length() const { return m_styleSheet->length(); }
-    virtual CSSRule* item(unsigned index) const { return m_styleSheet->item(index); }
+    virtual unsigned length() const OVERRIDE { return m_styleSheet->length(); }
+    virtual CSSRule* item(unsigned index) const OVERRIDE { return m_styleSheet->item(index); }
 
-    virtual CSSStyleSheet* styleSheet() const { return m_styleSheet; }
+    virtual CSSStyleSheet* styleSheet() const OVERRIDE { return m_styleSheet; }
 
     CSSStyleSheet* m_styleSheet;
 };
 
 #if !ASSERT_DISABLED
 static bool isAcceptableCSSStyleSheetParent(Node* parentNode)
 {
     // Only these nodes can be parents of StyleSheets, and they need to call clearOwnerNode() when moved out of document.
     return !parentNode
         || parentNode->isDocumentNode()
@@ skipping 309 matching lines @@
         root = root->parentStyleSheet();
     return root->ownerNode() ? &root->ownerNode()->document() : 0;
 }
 
 void CSSStyleSheet::clearChildRuleCSSOMWrappers()
 {
     m_childRuleCSSOMWrappers.clear();
 }
 
 }