Fix serialization of content property to always quote

Source/core/css/CSSValueList.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 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 65 matching lines @@
         newList = createSlashSeparated();
         break;
     default:
         ASSERT_NOT_REACHED();
     }
     for (size_t index = 0; index < m_values.size(); index++)
         newList->append(m_values[index]);
     return newList.release();
 }
 
-String CSSValueList::customCSSText(CSSTextFormattingFlags formattingFlag) const
+String CSSValueList::customCSSText() const
 {
     StringBuilder result;
     String separator;
     switch (m_valueListSeparator) {
     case SpaceSeparator:
         separator = " ";
         break;
     case CommaSeparator:
         separator = ", ";
         break;
     case SlashSeparator:
         separator = " / ";
         break;
     default:
         ASSERT_NOT_REACHED();
     }
 
     unsigned size = m_values.size();
     for (unsigned i = 0; i < size; i++) {
         if (!result.isEmpty())
             result.append(separator);
-        if (formattingFlag == AlwaysQuoteCSSString && m_values[i]->isPrimitiveValue())
-            result.append(toCSSPrimitiveValue(m_values[i].get())->customCSSText(AlwaysQuoteCSSString));
-        else
-            result.append(m_values[i]->cssText());
+        result.append(m_values[i]->cssText());
     }
 
     return result.toString();
 }
 
 bool CSSValueList::equals(const CSSValueList& other) const
 {
     return m_valueListSeparator == other.m_valueListSeparator && compareCSSValueVector(m_values, other.m_values);
 }
 
@@ skipping 15 matching lines @@
     return false;
 }
 
 DEFINE_TRACE_AFTER_DISPATCH(CSSValueList)
 {
     visitor->trace(m_values);
     CSSValue::traceAfterDispatch(visitor);
 }
 
 } // namespace blink