Have Element::ensureMutableInlineStyle() return a reference

Source/core/css/CSSStyleRule.cpp

 /*
  * (C) 1999-2003 Lars Knoll (knoll@kde.org)
  * (C) 2002-2003 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2002, 2005, 2006, 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.
  *
@@ skipping 95 matching lines @@
         selectorTextCache().remove(this);
         setHasCachedSelectorText(false);
     }
 }
 
 String CSSStyleRule::cssText() const
 {
     StringBuilder result;
     result.append(selectorText());
     result.appendLiteral(" { ");
-    String decls = m_styleRule->properties()->asText();
+    String decls = m_styleRule->properties().asText();
     result.append(decls);
     if (!decls.isEmpty())
         result.append(' ');
     result.append('}');
     return result.toString();
 }
 
 void CSSStyleRule::reattach(StyleRuleBase* rule)
 {
     ASSERT(rule);
     m_styleRule = toStyleRule(rule);
     if (m_propertiesCSSOMWrapper)
         m_propertiesCSSOMWrapper->reattach(m_styleRule->mutableProperties());
 }
 
 void CSSStyleRule::trace(Visitor* visitor)
 {
     visitor->trace(m_styleRule);
     CSSRule::trace(visitor);
 }
 
 } // namespace WebCore