Add toggleAll to CSSClassSet.

tests/html/element_classes_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/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:collection';
 import 'dart:html';
 
@@ skipping 124 matching lines @@
     classes.addAll(['bar', 'qux', 'bip']);
     expect(classes, orderedEquals(['foo', 'bar', 'baz', 'qux', 'bip']));
   });
 
   test('removeAll', () {
     final classes = makeClassSet();
     classes.removeAll(['bar', 'baz', 'qux']);
     expect(classes, orderedEquals(['foo']));
   });
 
+  test('toggleAll', () {
+    final classes = makeClassSet();
+    classes.toggleAll(['bar', 'foo']);
+    expect(classes, orderedEquals(['baz']));
+    classes.toggleAll(['qux', 'quux']);
+    expect(classes, orderedEquals(['baz', 'qux', 'quux']));
+  });
+
   test('isSubsetOf', () {
     final classes = makeClassSet();
     expect(classes.isSubsetOf(['foo', 'bar', 'baz'].toSet()), isTrue);
     expect(classes.isSubsetOf(['foo', 'bar', 'baz', 'qux'].toSet()), isTrue);
     expect(classes.isSubsetOf(['foo', 'bar', 'qux'].toSet()), isFalse);
   });
 
   test('containsAll', () {
     final classes = makeClassSet();
     expect(classes.containsAll(['foo', 'baz'].toSet()), isTrue);
@@ skipping 15 matching lines @@
   test('order', () {
     var classes = makeClassSet();
     classes.add('aardvark');
     expect(classes, orderedEquals(['foo', 'bar', 'baz', 'aardvark']));
     classes.toggle('baz');
     expect(classes, orderedEquals(['foo', 'bar', 'aardvark']));
     classes.toggle('baz');
     expect(classes, orderedEquals(['foo', 'bar', 'aardvark', 'baz']));
   });
 }