Revert "Enforce token syntax for CssClassSet arguments"

tests/html/svgelement_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 SvgElementTest;
 import 'dart:html';
 import 'dart:svg' as svg;
 import 'package:expect/expect.dart';
 import 'package:unittest/html_individual_config.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 406 matching lines @@
   group('css', () {
     test('classes', () {
       var el = new svg.CircleElement();
       var classes = el.classes;
       expect(el.classes.length, 0);
       classes.toggle('foo');
       expect(el.classes.length, 1);
       classes.toggle('foo');
       expect(el.classes.length, 0);
     });
-
-    test('classes-add-bad', () {
-      var el = new svg.CircleElement();
-      expect(() => el.classes.add(''), throws);
-      expect(() => el.classes.add('foo bar'), throws);
-    });
-    test('classes-remove-bad', () {
-      expect(() => el.classes.remove(''), throws);
-      expect(() => el.classes.remove('foo bar'), throws);
-    });
-    test('classes-toggle-token', () {
-      var el = new svg.CircleElement();
-      expect(() => el.classes.toggle(''), throws);
-      expect(() => el.classes.toggle('', true), throws);
-      expect(() => el.classes.toggle('', false), throws);
-      expect(() => el.classes.toggle('foo bar'), throws);
-      expect(() => el.classes.toggle('foo bar', true), throws);
-      expect(() => el.classes.toggle('foo bar', false), throws);
-    });
-    test('classes-contains-bad', () {
-      var el = new svg.CircleElement();
-      // Non-strings => false, strings must be valid tokens.
-      expect(el.classes.contains(1), isFalse);
-      expect(() => el.classes.contains(''), throws);
-      expect(() => el.classes.contains('foo bar'), throws);
-    });
   });
 
   group('getBoundingClientRect', () {
     test('is a Rectangle', () {
       var element = new svg.RectElement();
       element.attributes['width'] = '100';
       element.attributes['height'] = '100';
       var root = new svg.SvgSvgElement();
       root.append(element);
 
       document.body.append(root);
 
       var rect = element.getBoundingClientRect();
       expect(rect is Rectangle, isTrue);
       expect(rect.width, closeTo(100, 1));
       expect(rect.height, closeTo(100, 1));
     });
   });
 
   group('PathElement', () {
     test('pathSegList', () {
       svg.PathElement path =
           new svg.SvgElement.svg('<path d="M 100 100 L 300 100 L 200 300 z"/>');
       for (var seg in path.pathSegList) {
         expect(seg is svg.PathSeg, isTrue);
       }
     });
   });
 }