Use proper type in _createElement_2

tools/dom/templates/html/impl/impl_Document.darttemplate

Index: tools/dom/templates/html/impl/impl_Document.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Document.darttemplate b/tools/dom/templates/html/impl/impl_Document.darttemplate
index 8b9d22bc5f1f95f714936ff587cc31cd31dc7bc9..ca0705a37b5670f41eb739068aa7f5af20b8ec81 100644
--- a/tools/dom/templates/html/impl/impl_Document.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Document.darttemplate
@@ -92,13 +92,14 @@ $if DART2JS
   // The two-argument version of this is automatically generated, but we need to
   // omit the typeExtension if it's null on Firefox or we get an is="null" attribute.
   @DomName('Document.createElement')
-  _createElement_2(String tagName) => JS('', '#.createElement(#)', this, tagName);
+  _createElement_2(String tagName) =>
+      JS('Element', '#.createElement(#)', this, tagName);
 
   // The three-argument version of this is automatically generated, but we need to
   // omit the typeExtension if it's null on Firefox or we get an is="null" attribute.
   @DomName('Document.createElementNS')
   _createElementNS_2(String namespaceURI, String qualifiedName) =>
-      JS('', '#.createElementNS(#, #)', this, namespaceURI, qualifiedName);
+      JS('Element', '#.createElementNS(#, #)', this, namespaceURI, qualifiedName);
 
 $endif
   @DomName('Document.createElementNS')