Make 'where' lazy.

tests/html/node_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.
 
 library NodeTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:html';
 import 'dart:svg';
 
@@ skipping 61 matching lines @@
 
     test('forEach', () {
       var nodes = [];
       var node = makeNodeWithChildren();
       node.nodes.forEach((n) => nodes.add(n));
       expect(nodes[0], isText);
       expect(nodes[1], isBRElement);
       expect(nodes[2], isComment);
     });
 
-    test('filter', () {
-      var filtered = makeNodeWithChildren().nodes.where((n) => n is BRElement);
+    test('where', () {
+      var filtered =
+          makeNodeWithChildren().nodes.where((n) => n is BRElement).toList();
       expect(filtered.length, 1);
       expect(filtered[0], isBRElement);
       expect(filtered, isNodeList);
     });
 
     test('every', () {
       var node = makeNodeWithChildren();
       expect(node.nodes.every((n) => n is Node), isTrue);
       expect(node.nodes.every((n) => n is Comment), isFalse);
     });
@@ skipping 82 matching lines @@
     });
 
     test('getRange', () {
       var node = makeNodeWithChildren();
       expect(node.nodes.getRange(1, 2), isNodeList);
     });
   });
 
   group('_NodeList', () {
     List<Node> makeNodeList() =>
-      makeNodeWithChildren().nodes.where((_) => true);
+      makeNodeWithChildren().nodes.where((_) => true).toList();
 
     test('first', () {
       var nodes = makeNodeList();
       expect(nodes.first, isText);
     });
 
-    test('filter', () {
-      var filtered = makeNodeList().where((n) => n is BRElement);
+    test('where', () {
+      var filtered = makeNodeList().where((n) => n is BRElement).toList();
       expect(filtered.length, 1);
       expect(filtered[0], isBRElement);
       expect(filtered, isNodeList);
     });
 
     test('getRange', () {
       var range = makeNodeList().getRange(1, 2);
       expect(range, isNodeList);
       expect(range[0], isBRElement);
       expect(range[1], isComment);
     });
   });
 }