Use stricter typing for HTMLCollection named getter

Source/core/html/HTMLCollection.idl

Index: Source/core/html/HTMLCollection.idl
diff --git a/Source/core/html/HTMLCollection.idl b/Source/core/html/HTMLCollection.idl
index ab60afd1753ca8629d728a280403ef2c2a9d5563..2632e64de090e4a4955f3b474a716905d6abd8b6 100644
--- a/Source/core/html/HTMLCollection.idl
+++ b/Source/core/html/HTMLCollection.idl
@@ -25,7 +25,7 @@
 ] interface HTMLCollection {
     readonly attribute unsigned long length;
     getter Node item([Default=Undefined] optional unsigned long index);
-    Node namedItem([Default=Undefined] optional DOMString name);
-    [NotEnumerable, ImplementedAs=namedItem] getter Node ([Default=Undefined] optional DOMString name);
+    Element namedItem([Default=Undefined] optional DOMString name);
+    [NotEnumerable, ImplementedAs=namedItem] getter Element ([Default=Undefined] optional DOMString name);
 };