Have Element::ensureMutableInlineStyle() return a reference

Source/core/css/resolver/ViewportStyleResolver.cpp

 /*
  * Copyright (C) 2012-2013 Intel Corporation. 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 46 matching lines @@
 {
     rules->compactRulesIfNeeded();
 
     const WillBeHeapVector<RawPtrWillBeMember<StyleRuleViewport> >& viewportRules = rules->viewportRules();
     for (size_t i = 0; i < viewportRules.size(); ++i)
         addViewportRule(viewportRules[i], origin);
 }
 
 void ViewportStyleResolver::addViewportRule(StyleRuleViewport* viewportRule, Origin origin)
 {
-    StylePropertySet* propertySet = viewportRule->mutableProperties();
+    StylePropertySet& propertySet = viewportRule->mutableProperties();
 
-    unsigned propertyCount = propertySet->propertyCount();
+    unsigned propertyCount = propertySet.propertyCount();
     if (!propertyCount)
         return;
 
     if (origin == AuthorOrigin)
         m_hasAuthorStyle = true;
 
     if (!m_propertySet) {
-        m_propertySet = propertySet->mutableCopy();
+        m_propertySet = propertySet.mutableCopy();
         return;
     }
 
     // We cannot use mergeAndOverrideOnConflict() here because it doesn't
     // respect the !important declaration (but addParsedProperty() does).
     for (unsigned i = 0; i < propertyCount; ++i)
-        m_propertySet->addParsedProperty(propertySet->propertyAt(i).toCSSProperty());
+        m_propertySet->addParsedProperty(propertySet.propertyAt(i).toCSSProperty());
 }
 
 void ViewportStyleResolver::clearDocument()
 {
     m_document = 0;
 }
 
 void ViewportStyleResolver::resolve()
 {
     if (!m_document)
@@ skipping 105 matching lines @@
 
     Length result = primitiveValue->convertToLength<AnyConversion>(CSSToLengthConversionData(documentStyle, documentStyle, width, height, 1.0f));
     if (documentStyle->hasViewportUnits())
         m_document->setHasViewportUnits();
     documentStyle->setHasViewportUnits(documentStyleHasViewportUnits);
 
     return result;
 }
 
 } // namespace WebCore