Consistently cache ElementData::length() before loops

Source/core/xml/parser/XMLDocumentParser.cpp

Index: Source/core/xml/parser/XMLDocumentParser.cpp
diff --git a/Source/core/xml/parser/XMLDocumentParser.cpp b/Source/core/xml/parser/XMLDocumentParser.cpp
index 8b42fb6076ddafde1ffd701d2f62d38772225a26..ea43a5e01ad527f848805cbcf2e901a65bf4e335 100644
--- a/Source/core/xml/parser/XMLDocumentParser.cpp
+++ b/Source/core/xml/parser/XMLDocumentParser.cpp
@@ -837,7 +837,8 @@ XMLDocumentParser::XMLDocumentParser(DocumentFragment* fragment, Element* parent
     for (; !elemStack.isEmpty(); elemStack.removeLast()) {
         Element* element = elemStack.last();
         if (element->hasAttributes()) {
-            for (unsigned i = 0; i < element->attributeCount(); i++) {
+            unsigned attributeCount = element->attributeCount();
+            for (unsigned i = 0; i < attributeCount; ++i) {
                 const Attribute* attribute = element->attributeItem(i);
                 if (attribute->localName() == xmlnsAtom)
                     m_defaultNamespaceURI = attribute->value();