Fix factories in Frog to correspond to the new syntax.

frog/leg/util/link_implementation.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// TODO(ahe): This class should not be generic.
-class LinkFactory {
-  factory Link<T>(T head, [Link<T> tail]) {
+class LinkFactory<T> {
+  factory Link(T head, [Link<T> tail]) {
     if (tail === null) {
       tail = new LinkTail<T>();
     }
     return new LinkEntry<T>(head, tail);
   }
 
-  factory Link<T>.fromList(List<T> list) {
+  factory Link.fromList(List<T> list) {
     switch (list.length) {
       case 0:
         return new LinkTail<T>();
       case 1:
         return new Link<T>(list[0]);
       case 2:
         return new Link<T>(list[0], new Link<T>(list[1]));
       case 3:
         return new Link<T>(list[0], new Link<T>(list[1], new Link<T>(list[2])));
     }
@@ skipping 98 matching lines @@
   void addLast(T t) {
     LinkEntry<T> entry = new LinkEntry<T>(t, null);
     if (head === null) {
       head = entry;
     } else {
       lastLink.tail = entry;
     }
     lastLink = entry;
   }
 }