Drop const_iterator for AttributeCollection

Source/core/css/SelectorChecker.h

Index: Source/core/css/SelectorChecker.h
diff --git a/Source/core/css/SelectorChecker.h b/Source/core/css/SelectorChecker.h
index c93b941e75926b9bc5bd1167331af029dd3758b1..4d1b27ef7253631815a2c909dda168b8559f3601 100644
--- a/Source/core/css/SelectorChecker.h
+++ b/Source/core/css/SelectorChecker.h
@@ -166,8 +166,8 @@ inline bool SelectorChecker::tagMatches(const Element& element, const QualifiedN
 inline bool SelectorChecker::checkExactAttribute(const Element& element, const QualifiedName& selectorAttributeName, const StringImpl* value)
 {
     AttributeCollection attributes = element.attributesWithoutUpdate();
-    AttributeCollection::const_iterator end = attributes.end();
-    for (AttributeCollection::const_iterator it = attributes.begin(); it != end; ++it) {
+    AttributeCollection::iterator end = attributes.end();
+    for (AttributeCollection::iterator it = attributes.begin(); it != end; ++it) {
         if (it->matches(selectorAttributeName) && (!value || it->value().impl() == value))
             return true;
     }