Have Element::ensureMutableInlineStyle() return a reference

Source/core/editing/EditingStyle.cpp

Index: Source/core/editing/EditingStyle.cpp
diff --git a/Source/core/editing/EditingStyle.cpp b/Source/core/editing/EditingStyle.cpp
index aed258cb73b2707f6588c63afec3c4e22cd4f8d0..0d555c04bde1cfc481cbaed227d431cc1525763c 100644
--- a/Source/core/editing/EditingStyle.cpp
+++ b/Source/core/editing/EditingStyle.cpp
@@ -1118,7 +1118,7 @@ static PassRefPtr<MutableStylePropertySet> styleFromMatchedRulesForElement(Eleme
     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();
 }