Added shim for scrollX and scrollY for IE 9.

tests/html/window_test.dart

Index: tests/html/window_test.dart
diff --git a/tests/html/b_element_test.dart b/tests/html/window_test.dart
similarity index 60%
copy from tests/html/b_element_test.dart
copy to tests/html/window_test.dart
index 1cd71b6a1e7800b8ff62c18a6438f6bca7dd5f1e..a663d1be16df9e1c8aa5d41fa1222ecdebb2794b 100644
--- a/tests/html/b_element_test.dart
+++ b/tests/html/window_test.dart
@@ -1,4 +1,4 @@
-library BElementTest;
+library WindowTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
@@ -6,8 +6,8 @@ import 'dart:html';
 main() {
   useHtmlConfiguration();
 
-  test('create b', () {
-    new Element.tag('b');
+  test('scrollXY', () {
+    expect(window.scrollX, 0);
+    expect(window.scrollY, 0);
   });
 }
-