Changes in polymer-expressions to prepare for codegen in polymer:

pkg/polymer_expressions/test/eval_test.dart

 // Copyright (c) 2013, 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.
 
 library eval_test;
 
 import 'dart:async';
 
 // Import mirrors to cause all mirrors to be retained by dart2js.
 // The tests reflect on LinkedHashMap.length and String.length.
@@ skipping 277 matching lines @@
       expect(() => scope['a'], throwsException);
     });
 
     test('should return variables', () {
       var scope = new Scope(variables: {'a': 'A'});
       expect(scope['a'], 'A');
     });
 
     test("should a field from the parent's model", () {
       var parent = new Scope(variables: {'a': 'A', 'b': 'B'});
-      var child = new Scope(variables: {'a': 'a'}, parent: parent);
+      var child = parent.childScope('a', 'a');
       expect(child['a'], 'a');
       expect(parent['a'], 'A');
       expect(child['b'], 'B');
     });
 
   });
 
   group('observe', () {
     test('should observe an identifier', () {
       var foo = new Foo(name: 'foo');
@@ skipping 120 matching lines @@
   return Future.wait([future, new Future(() {
     expect(passed, true, reason: "Didn't receive a change notification on $s");
   })]);
 }
 
 // Regression test from https://code.google.com/p/dart/issues/detail?id=13459
 class WordElement extends Observable {
   @observable List chars1 = 'abcdefg'.split('');
   @reflectable List filteredList(List original) => [original[0], original[1]];
 }