Make ensureDefaultStyleSheetForElement parameter const reference.

Source/core/css/resolver/StyleResolver.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 584 matching lines @@
             bool forceVisited = InspectorInstrumentation::forcePseudoState(element, CSSSelector::PseudoVisited);
             if (forceVisited)
                 linkState = InsideVisitedLink;
         }
         state.style()->setInsideLink(linkState);
     }
 
     if (!baseComputedStyle) {
 
         bool needsCollection = false;
-        CSSDefaultStyleSheets::instance().ensureDefaultStyleSheetsForElement(element, needsCollection);
+        CSSDefaultStyleSheets::instance().ensureDefaultStyleSheetsForElement(*element, needsCollection);
         if (needsCollection)
             collectFeatures();
 
         ElementRuleCollector collector(state.elementContext(), m_selectorFilter, state.style());
 
         matchAllRules(state, collector, matchingBehavior != MatchAllRulesExcludingSMIL);
 
         if (element->computedStyle() && element->computedStyle()->textAutosizingMultiplier() != state.style()->textAutosizingMultiplier()) {
             // Preserve the text autosizing multiplier on style recalc. Autosizer will update it during layout if needed.
             // NOTE: this must occur before applyMatchedProperties for correct computation of font-relative lengths.
@@ skipping 883 matching lines @@
     visitor->trace(m_watchedSelectorsRules);
     visitor->trace(m_treeBoundaryCrossingRules);
     visitor->trace(m_styleResourceLoader);
     visitor->trace(m_styleSharingLists);
     visitor->trace(m_pendingStyleSheets);
     visitor->trace(m_document);
 #endif
 }
 
 } // namespace blink