Make Map.keys/values Iterables.

utils/apidoc/mdn/prettyPrint.dart

 /**
  * Creates database.html, examples.html, and obsolete.html.
  */
 
 library prettyPrint;
 
 import 'dart:io';
 import 'dart:json' as json;
 import 'util.dart';
 
 String orEmpty(String str) {
   return str == null ? "" : str;
 }
 
-List<String> sortStringCollection(Collection<String> collection) {
+List<String> sortStringCollection(Iterable<String> collection) {
   final out = <String>[];
   out.addAll(collection);
   out.sort((String a, String b) => a.compareTo(b));
   return out;
 }
 
 int addMissing(StringBuffer sb, String type, Map members) {
   int total = 0;
   /**
    * Add all missing members to the string output and return the number of
@@ skipping 395 matching lines @@
           <th>IDL</th>
           <th>Status</th>
         </tr>
 $sbObsolete
     </tbody>
    </table>
   </body>
  </html>
  """);
 }