Make getKeys, getValues getters (keys, values).

tests/language/ct_const_test.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.
 // All things regarding compile time constant expressions.
 
 interface Roman {
   static const I = 1;
   static const II = 2;
   static const III = 3;
   static const IV = 4;
@@ skipping 64 matching lines @@
     final c11dBelgium = const {"black": 1, "yellow": 2, "red": 3};
     Expect.equals(false, c11dGermany1 == c11dBelgium);
     Expect.equals(false, c11dGermany1 === c11dBelgium);
 
     final c11dItaly = const {"green": 1, "red": 3, "white": 2};
     Expect.equals(true,
         c11dItaly === const {"green": 1, "red": 3, "white": 2});
     Expect.equals(true, c11dItaly === Roman.VivaItalia);
 
     Expect.equals(3, c11dItaly.length);
-    Expect.equals(3, c11dItaly.getKeys().length);
+    Expect.equals(3, c11dItaly.keys.length);
     Expect.equals(true, c11dItaly.containsKey("white"));
     Expect.equals(false, c11dItaly.containsKey("black"));
 
     // Make sure the map object is immutable.
     bool caughtException = false;
     try {
       c11dItaly["green"] = 0;
     } on UnsupportedError catch (e) {
       caughtException = true;
     }
@@ skipping 18 matching lines @@
     Expect.equals(true, caughtException);
     Expect.equals(1, c11dItaly["green"]);
 
     Expect.equals(true, null === naught);
   }
 }
 
 main() {
   CTConstTest.testMain();
 }