Avoid looping through all attributes for attribute selector.

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 456 matching lines @@
     bool caseInsensitive = selector.attributeMatchType() == CSSSelector::CaseInsensitive;
 
     AttributeCollection attributes = element.attributesWithoutUpdate();
     for (const auto& attributeItem: attributes) {
         if (!attributeItem.matches(selectorAttr))
             continue;
 
         if (attributeValueMatches(attributeItem, match, selectorValue, !caseInsensitive))
             return true;
 
-        if (caseInsensitive)
+        if (caseInsensitive) {
+            if (selectorAttr.namespaceURI() != starAtom)
+                return false;
             continue;
+        }
 
         // Legacy dictates that values of some attributes should be compared in
         // a case-insensitive manner regardless of whether the case insensitive
         // flag is set or not.
         bool legacyCaseInsensitive = element.document().isHTMLDocument() && !HTMLDocument::isCaseSensitiveAttribute(selectorAttr);
 
         // If case-insensitive, re-check, and count if result differs.
         // See http://code.google.com/p/chromium/issues/detail?id=327060
         if (legacyCaseInsensitive && attributeValueMatches(attributeItem, match, selectorValue, false)) {
             UseCounter::count(element.document(), UseCounter::CaseInsensitiveAttrSelectorMatch);
             return true;
         }
+        if (selectorAttr.namespaceURI() != starAtom)
+            return false;
     }
 
     return false;
 }
 
 template<typename SiblingTraversalStrategy>
 bool SelectorChecker::checkOne(const SelectorCheckingContext& context, const SiblingTraversalStrategy& siblingTraversalStrategy, unsigned* specificity) const
 {
     ASSERT(context.element);
     Element& element = *context.element;
@@ skipping 672 matching lines @@
     return isHTMLSelectElement(element) && !toHTMLSelectElement(element).usesMenuList();
 }
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const DOMSiblingTraversalStrategy&, MatchResult*) const;
 
 template
 SelectorChecker::Match SelectorChecker::match(const SelectorCheckingContext&, const ShadowDOMSiblingTraversalStrategy&, MatchResult*) const;
 
 }