Fix counters() separator serialization

Source/core/css/CSSPrimitiveValue.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 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 995 matching lines @@
             StringBuilder result;
             String separator = m_value.counter->separator();
             if (separator.isEmpty())
                 result.appendLiteral("counter(");
             else
                 result.appendLiteral("counters(");
 
             result.append(m_value.counter->identifier());
             if (!separator.isEmpty()) {
                 result.appendLiteral(", ");
-                result.append(quoteCSSStringIfNeeded(separator));
+                result.append(serializeString(separator));
             }
             String listStyle = m_value.counter->listStyle();
             if (!listStyle.isEmpty()) {
                 result.appendLiteral(", ");
                 result.append(listStyle);
             }
             result.append(')');
 
             text = result.toString();
             break;
@@ skipping 112 matching lines @@
         visitor->trace(m_value.shape);
         break;
     default:
         break;
     }
 #endif
     CSSValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink