Rename DOMURL to ObjectUrl.

tests/html/url_test.dart

 // Copyright (c) 2012, 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 url_test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 
 main() {
@@ skipping 18 matching lines @@
       dataArray[i] = byteString.charCodeAt(i);
     }
 
     var blob = new Blob([arrayBuffer], 'image/png');
     return blob;
   }
 
   group('blob', () {
     test('createObjectUrl', () {
       var blob = createImageBlob();
-      var url = window.createObjectUrl(blob);
+      var url = Url.createObjectUrl(blob);
       expect(url.length, greaterThan(0));
       expect(url, startsWith('blob:'));
 
       var img = new ImageElement();
       img.on.load.add(expectAsync1((_) {
         expect(img.complete, true);
       }));
       img.on.error.add((_) {
         guardAsync(() {
           expect(true, isFalse, reason: 'URL failed to load.');
         });
       });
       img.src = url;
     });
 
     test('revokeObjectUrl', () {
       var blob = createImageBlob();
-      var url = window.createObjectUrl(blob);
+      var url = Url.createObjectUrl(blob);
       expect(url, startsWith('blob:'));
-      window.revokeObjectUrl(url);
+      Url.revokeObjectUrl(url);
 
       var img = new ImageElement();
       // Image should fail to load since the URL was revoked.
       img.on.error.add(expectAsync1((_) {
       }));
       img.on.load.add((_) {
         guardAsync(() {
           expect(true, isFalse, reason: 'URL should not have loaded.');
         });
       });
       img.src = url;
     });
 
   });
 }