Have SelectorQuery API take rootNode by reference

Source/core/css/SelectorCheckerFastPath.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 18 matching lines @@
 #ifndef SelectorCheckerFastPath_h
 #define SelectorCheckerFastPath_h
 
 #include "core/css/CSSSelector.h"
 #include "core/css/SelectorChecker.h"
 
 namespace WebCore {
 
 class SelectorCheckerFastPath {
 public:
-    SelectorCheckerFastPath(const CSSSelector*, const Element*);
+    SelectorCheckerFastPath(const CSSSelector*, const Element&);
 
     bool matches() const;
     bool matchesRightmostSelector(SelectorChecker::VisitedMatchType) const;
     bool matchesRightmostAttributeSelector() const;
 
     static bool canUse(const CSSSelector*);
 
 private:
     bool commonPseudoClassSelectorMatches(SelectorChecker::VisitedMatchType) const;
 
     const CSSSelector* m_selector;
-    const Element* m_element;
+    const Element& m_element;
 };
 
 inline bool SelectorCheckerFastPath::matchesRightmostAttributeSelector() const
 {
     if (m_selector->m_match == CSSSelector::Exact || m_selector->m_match == CSSSelector::Set)
         return SelectorChecker::checkExactAttribute(m_element, m_selector->attribute(), m_selector->value().impl());
     ASSERT(!m_selector->isAttributeSelector());
     return true;
 }
 
 }
 
 #endif