Make isEmpty a getter.

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/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 Node makeNode() => new Element.tag('div');
@@ skipping 70 matching lines @@
       Expect.isFalse(node.nodes.every((n) => n is Comment));
     });
 
     test('some', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes.some((n) => n is Comment));
       Expect.isFalse(node.nodes.some((n) => n is SVGElement));
     });
 
     test('isEmpty', () {
-      Expect.isTrue(makeNode().nodes.isEmpty());
-      Expect.isFalse(makeNodeWithChildren().nodes.isEmpty());
+      Expect.isTrue(makeNode().nodes.isEmpty);
+      Expect.isFalse(makeNodeWithChildren().nodes.isEmpty);
     });
 
     test('length', () {
       Expect.equals(0, makeNode().nodes.length);
       Expect.equals(3, makeNodeWithChildren().nodes.length);
     });
 
     test('[]', () {
       var node = makeNodeWithChildren();
       Expect.isTrue(node.nodes[0] is Text);
@@ skipping 84 matching lines @@
     });
 
     test('getRange', () {
       var range = makeNodeList().getRange(1, 2);
       Expect.isTrue(range is List<Node>);
       Expect.isTrue(range[0] is BRElement);
       Expect.isTrue(range[1] is Comment);
     });
   });
 }