Have Element::ensureMutableInlineStyle() return a reference

Source/core/editing/EditingStyle.cpp

 /*
  * Copyright (C) 2007, 2008, 2009 Apple Computer, Inc.
  * Copyright (C) 2010, 2011 Google Inc. 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.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1100 matching lines @@
             m_mutableStyle->setProperty(property.id(), property.value()->cssText(), property.isImportant());
     }
 }
 
 static PassRefPtr<MutableStylePropertySet> styleFromMatchedRulesForElement(Element* element, unsigned rulesToInclude)
 {
     RefPtr<MutableStylePropertySet> style = MutableStylePropertySet::create();
     RefPtr<StyleRuleList> matchedRules = element->document().ensureStyleResolver().styleRulesForElement(element, rulesToInclude);
     if (matchedRules) {
         for (unsigned i = 0; i < matchedRules->m_list.size(); ++i)
-            style->mergeAndOverrideOnConflict(matchedRules->m_list[i]->properties());
+            style->mergeAndOverrideOnConflict(&matchedRules->m_list[i]->properties());
     }
     return style.release();
 }
 
 void EditingStyle::mergeStyleFromRules(Element* element)
 {
     RefPtr<MutableStylePropertySet> styleFromMatchedRules = styleFromMatchedRulesForElement(element,
         StyleResolver::AuthorCSSRules | StyleResolver::CrossOriginCSSRules);
     // Styles from the inline style declaration, held in the variable "style", take precedence
     // over those from matched rules.
@@ skipping 500 matching lines @@
 {
     for (Node* ancestor = node; ancestor; ancestor = ancestor->parentNode()) {
         RefPtr<CSSComputedStyleDeclaration> ancestorStyle = CSSComputedStyleDeclaration::create(ancestor);
         if (!hasTransparentBackgroundColor(ancestorStyle.get()))
             return ancestorStyle->getPropertyCSSValue(CSSPropertyBackgroundColor);
     }
     return nullptr;
 }
 
 }