Make getKeys, getValues getters (keys, values).

samples/ui_lib/layout/GridTracks.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.
 
 // This file has classes representing the grid tracks and grid template
 
 /**
  * The data structure representing the grid-rows or grid-columns
  * properties.
  */
@@ skipping 109 matching lines @@
         final rect = _rects[cell];
         if (rect != null) {
           rect.add(r + 1, c + 1);
         } else {
           _rects[cell] = new _GridTemplateRect(cell, r + 1, c + 1);
         }
       }
     }
 
     // Finally, check that each rectangle is valid (i.e. all spaces filled)
-    for (final rect in _rects.getValues()) {
+    for (final rect in _rects.values) {
       rect.checkValid();
     }
   }
 
   /**
    * Looks up the given cell in the template, and returns the rect.
    */
   _GridTemplateRect lookupCell(String cell) {
     if (cell.length != 1) {
       throw new UnsupportedError(
@@ skipping 37 matching lines @@
 /**
  * Used to return a row/column and span during parsing of grid-row and
  * grid-column during parsing.
  */
 class _GridLocation {
   final int start, length;
   _GridLocation(this.start, this.length) {}
 
   int get end => start + length;
 }