Make Element::attributes() less error-prone and simplify call sites

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 445 matching lines @@
 
 static bool anyAttributeMatches(Element& element, CSSSelector::Match match, const CSSSelector& selector)
 {
     const QualifiedName& selectorAttr = selector.attribute();
     ASSERT(selectorAttr.localName() != starAtom); // Should not be possible from the CSS grammar.
 
     // Synchronize the attribute in case it is lazy-computed.
     // Currently all lazy properties have a null namespace, so only pass localName().
     element.synchronizeAttribute(selectorAttr.localName());
 
-    if (!element.hasAttributesWithoutUpdate())
-        return false;
-
     const AtomicString& selectorValue = selector.value();
     bool caseInsensitive = selector.attributeMatchType() == CSSSelector::CaseInsensitive;
 
-    AttributeCollection attributes = element.attributes();
+    AttributeCollection attributes = element.attributesWithoutUpdate();
     AttributeCollection::const_iterator end = attributes.end();
     for (AttributeCollection::const_iterator it = attributes.begin(); it != end; ++it) {
         const Attribute& attributeItem = *it;
 
         if (!attributeItem.matches(selectorAttr))
             continue;
 
         if (attributeValueMatches(attributeItem, match, selectorValue, !caseInsensitive))
             return true;
 
@@ skipping 649 matching lines @@
     return isHTMLOptionElement(element) && toHTMLOptionElement(element).spatialNavigationFocused() && isFrameFocused(element);
 }
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const DOMSiblingTraversalStrategy&, MatchResult*) const;
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const ShadowDOMSiblingTraversalStrategy&, MatchResult*) const;
 
 }