Make isEmpty a getter.

tests/html/element_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('ElementTest');
 #import('../../pkg/unittest/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 expectLargeRect(ClientRect rect) {
@@ skipping 512 matching lines @@
       Expect.isFalse(el.elements.every((n) => n is InputElement));
     });
 
     test('some', () {
       var el = makeElementWithChildren();
       Expect.isTrue(el.elements.some((n) => n is InputElement));
       Expect.isFalse(el.elements.some((n) => n is SVGElement));
     });
 
     test('isEmpty', () {
-      Expect.isTrue(makeElement().elements.isEmpty());
-      Expect.isFalse(makeElementWithChildren().elements.isEmpty());
+      Expect.isTrue(makeElement().elements.isEmpty);
+      Expect.isFalse(makeElementWithChildren().elements.isEmpty);
     });
 
     test('length', () {
       Expect.equals(0, makeElement().elements.length);
       Expect.equals(3, makeElementWithChildren().elements.length);
     });
 
     test('[]', () {
       var el = makeElementWithChildren();
       Expect.isTrue(el.elements[0] is BRElement);
@@ skipping 120 matching lines @@
       Expect.isFalse(el.every((n) => n is SpanElement));
     });
 
     test('some', () {
       var el = getQueryAll();
       Expect.isTrue(el.some((n) => n is SpanElement));
       Expect.isFalse(el.some((n) => n is SVGElement));
     });
 
     test('isEmpty', () {
-      Expect.isTrue(getEmptyQueryAll().isEmpty());
-      Expect.isFalse(getQueryAll().isEmpty());
+      Expect.isTrue(getEmptyQueryAll().isEmpty);
+      Expect.isFalse(getQueryAll().isEmpty);
     });
 
     test('length', () {
       Expect.equals(0, getEmptyQueryAll().length);
       Expect.equals(3, getQueryAll().length);
     });
 
     test('[]', () {
       var els = getQueryAll();
       Expect.isTrue(els[0] is AnchorElement);
@@ skipping 52 matching lines @@
     });
 
     test('getRange', () {
       var range = makeElList().getRange(1, 2);
       Expect.isTrue(range is List<Element>);
       Expect.isTrue(range[0] is ImageElement);
       Expect.isTrue(range[1] is InputElement);
     });
   });
 }