Have Element::ensureMutableInlineStyle() return a reference

Source/core/css/CSSFilterRule.cpp

 /*
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 47 matching lines @@
 
 String CSSFilterRule::cssText() const
 {
     StringBuilder result;
     result.appendLiteral("@-webkit-filter ");
 
     String filterName = m_filterRule->filterName();
     result.append(filterName);
     result.appendLiteral(" { ");
 
-    String descs = m_filterRule->properties()->asText();
+    String descs = m_filterRule->properties().asText();
     result.append(descs);
     if (!descs.isEmpty())
         result.append(' ');
     result.append('}');
 
     return result.toString();
 }
 
 void CSSFilterRule::reattach(StyleRuleBase* rule)
 {
     ASSERT(rule);
     m_filterRule = toStyleRuleFilter(rule);
     if (m_propertiesCSSOMWrapper)
         m_propertiesCSSOMWrapper->reattach(m_filterRule->mutableProperties());
 }
 
 void CSSFilterRule::trace(Visitor* visitor)
 {
     visitor->trace(m_filterRule);
     CSSRule::trace(visitor);
 }
 
 } // namespace WebCore