Add iterator object to iterate efficiently over an Element's attributes

Source/core/css/SelectorChecker.cpp

Index: Source/core/css/SelectorChecker.cpp
diff --git a/Source/core/css/SelectorChecker.cpp b/Source/core/css/SelectorChecker.cpp
index 0e38d6fbe39d3bbf228323b4f6f2d4c6f74c9f2c..1aca118f0cd14dc10686796cad6194bdb724d680 100644
--- a/Source/core/css/SelectorChecker.cpp
+++ b/Source/core/css/SelectorChecker.cpp
@@ -492,9 +492,10 @@ static bool anyAttributeMatches(Element& element, CSSSelector::Match match, cons
 
     const AtomicString& selectorValue =  selector.value();
 
-    unsigned attributeCount = element.attributeCount();
-    for (size_t i = 0; i < attributeCount; ++i) {
-        const Attribute& attributeItem = element.attributeItem(i);
+    AttributeIteratorAccessor attributes = element.attributesIterator();

[esprehn, 2014/05/28 20:03:54]

This accessor thing is kind of weird, why can't Element have the iterator
methods?

+    AttributeConstIterator end = attributes.end();
+    for (AttributeConstIterator it = attributes.begin(); it != end; ++it) {
+        const Attribute& attributeItem = **it;
 
         if (!attributeItem.matches(selectorAttr))
             continue;