Make getKeys, getValues getters (keys, values).

samples/ui_lib/util/CollectionUtils.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.
 
 typedef num NumericValueSelector<T>(T value);
 
 /**
  * General purpose collection utilities.
  * TODO(jmesserly): make these top level functions?
  */
@@ skipping 114 matching lines @@
       do {
         total += iter.next();
       } while (iter.hasNext);
     }
     return total;
   }
 
   // TODO(jmesserly): something like should exist on Map, either a method or a
   // constructor, see bug #5340679
   static void copyMap(Map dest, Map source) {
-    for (final k in source.getKeys()) {
+    for (final k in source.keys) {
       dest[k] = source[k];
     }
   }
 }