Lots of frog cleanup

frog/lib/string_base.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.
 
 class StringBase {
   // TODO(jmesserly): this array copy is really unfortunate
   // TODO(jmesserly): check the performance of String.fromCharCode.apply
   // TODO(jmesserly): fix the generated JS name of factory ctors,
   // they shouldn't be duplicating the name.
   static String createFromCharCodes(List<int> charCodes) native @'''
 if (Object.getPrototypeOf(charCodes) !== Array.prototype) {
   charCodes = new ListFactory.ListFactory$from$factory(charCodes);
 }
 return String.fromCharCode.apply(null, charCodes);
 ''' {
+   // we may need to iterate over charCodes
+    var i = charCodes.iterator();  i.next(); i.hasNext();
     new ListFactory.from(charCodes); // ensure List.from is generated
   }
 
   static String join(List<String> strings, String separator) {
     if (strings.length == 0) return '';
     String s = strings[0];
     for (int i = 1; i < strings.length; i++) {
       s = s + separator + strings[i];
     }
     return s;
   }
 
   static String concatAll(List<String> strings) => join(strings, "");
 }