Pass implementation object to supplemental classes by reference

Source/core/css/SelectorChecker.cpp

 /*
  * 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 804 matching lines @@
                     break;
                 return true;
             }
         case CSSSelector::PseudoFullScreen:
             // While a Document is in the fullscreen state, and the document's current fullscreen
             // element is an element in the document, the 'full-screen' pseudoclass applies to
             // that element. Also, an <iframe>, <object> or <embed> element whose child browsing
             // context's Document is in the fullscreen state has the 'full-screen' pseudoclass applied.
             if (element.isFrameElementBase() && element.containsFullScreenElement())
                 return true;
-            if (FullscreenElementStack* fullscreen = FullscreenElementStack::fromIfExists(&element.document())) {
+            if (FullscreenElementStack* fullscreen = FullscreenElementStack::fromIfExists(element.document())) {
                 if (!fullscreen->webkitIsFullScreen())
                     return false;
                 return element == fullscreen->webkitCurrentFullScreenElement();
             }
             return false;
         case CSSSelector::PseudoFullScreenAncestor:
             return element.containsFullScreenElement();
         case CSSSelector::PseudoFullScreenDocument:
             // While a Document is in the fullscreen state, the 'full-screen-document' pseudoclass applies
             // to all elements of that Document.
-            if (!FullscreenElementStack::isFullScreen(&element.document()))
+            if (!FullscreenElementStack::isFullScreen(element.document()))
                 return false;
             return true;
         case CSSSelector::PseudoInRange:
             element.document().setContainsValidityStyleRules();
             return element.isInRange();
         case CSSSelector::PseudoOutOfRange:
             element.document().setContainsValidityStyleRules();
             return element.isOutOfRange();
         case CSSSelector::PseudoFutureCue:
             return (element.isVTTElement() && !toVTTElement(element).isPastNode());
@@ skipping 234 matching lines @@
     return element.focused() && isFrameFocused(element);
 }
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const DOMSiblingTraversalStrategy&, MatchResult*) const;
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const ShadowDOMSiblingTraversalStrategy&, MatchResult*) const;
 
 }