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

Source/core/dom/PresentationAttributeStyle.cpp

Index: Source/core/dom/PresentationAttributeStyle.cpp
diff --git a/Source/core/dom/PresentationAttributeStyle.cpp b/Source/core/dom/PresentationAttributeStyle.cpp
index 3d9a3e35496002585144b1fc427368e391cafac9..38cca3f2bd2171f3b99cf31f86b910d74362fd7d 100644
--- a/Source/core/dom/PresentationAttributeStyle.cpp
+++ b/Source/core/dom/PresentationAttributeStyle.cpp
@@ -123,17 +123,17 @@ static void makePresentationAttributeCacheKey(Element& element, PresentationAttr
     // Interpretation of the size attributes on <input> depends on the type attribute.
     if (isHTMLInputElement(element))
         return;
-    unsigned size = element.attributeCount();
-    for (unsigned i = 0; i < size; ++i) {
-        const Attribute& attribute = element.attributeItem(i);
-        if (!element.isPresentationAttribute(attribute.name()))
+    AttributeIteratorAccessor attributes = element.attributesIterator();
+    AttributeConstIterator end = attributes.end();
+    for (AttributeConstIterator it = attributes.begin(); it != end; ++it) {
+        if (!element.isPresentationAttribute(it->name()))
             continue;
-        if (!attribute.namespaceURI().isNull())
+        if (!it->namespaceURI().isNull())
             return;
         // FIXME: Background URL may depend on the base URL and can't be shared. Disallow caching.
-        if (attribute.name() == backgroundAttr)
+        if (it->name() == backgroundAttr)
             return;
-        result.attributesAndValues.append(std::make_pair(attribute.localName().impl(), attribute.value()));
+        result.attributesAndValues.append(std::make_pair(it->localName().impl(), it->value()));
     }
     if (result.attributesAndValues.isEmpty())
         return;
@@ -178,11 +178,10 @@ PassRefPtr<StylePropertySet> computePresentationAttributeStyle(Element& element)
         cacheCleaner.didHitPresentationAttributeCache();
     } else {
         style = MutableStylePropertySet::create(element.isSVGElement() ? SVGAttributeMode : HTMLAttributeMode);
-        unsigned size = element.attributeCount();
-        for (unsigned i = 0; i < size; ++i) {
-            const Attribute& attribute = element.attributeItem(i);
-            element.collectStyleForPresentationAttribute(attribute.name(), attribute.value(), toMutableStylePropertySet(style));
-        }
+        AttributeIteratorAccessor attributes = element.attributesIterator();
+        AttributeConstIterator end = attributes.end();
+        for (AttributeConstIterator it = attributes.begin(); it != end; ++it)
+            element.collectStyleForPresentationAttribute(it->name(), it->value(), toMutableStylePropertySet(style));
     }
 
     if (!cacheHash || cacheValue->value)