Return reference from styleEngine() accessor.

Source/core/dom/ContainerNode.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2013 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 1278 matching lines @@
     bool forceCheckOfAnyElementSibling = false;
     Document& document = this->document();
 
     for (Element* child = ElementTraversal::firstChild(*this); child; child = ElementTraversal::nextSibling(*child)) {
         bool childRulesChanged = child->needsStyleRecalc() && child->styleChangeType() >= SubtreeStyleChange;
 
         if (forceCheckOfNextElementCount || forceCheckOfAnyElementSibling)
             child->setNeedsStyleRecalc(SubtreeStyleChange, StyleChangeReasonForTracing::create(StyleChangeReason::SiblingSelector));
 
         if (childRulesChanged && hasDirectAdjacentRules)
-            forceCheckOfNextElementCount = document.styleEngine()->maxDirectAdjacentSelectors();
+            forceCheckOfNextElementCount = document.styleEngine().maxDirectAdjacentSelectors();
         else if (forceCheckOfNextElementCount)
             --forceCheckOfNextElementCount;
 
         forceCheckOfAnyElementSibling = forceCheckOfAnyElementSibling || (childRulesChanged && hasIndirectAdjacentRules);
     }
 }
 
 void ContainerNode::checkForSiblingStyleChanges(SiblingCheckType changeType, Node* nodeBeforeChange, Node* nodeAfterChange)
 {
     if (!inActiveDocument() || document().hasPendingForcedStyleRecalc() || styleChangeType() >= SubtreeStyleChange)
@@ skipping 168 matching lines @@
         return true;
 
     if (node->isElementNode() && toElement(node)->shadow())
         return true;
 
     return false;
 }
 #endif
 
 } // namespace blink