Added shim for scrollX and scrollY for IE 9.

sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index a4f487cfd8b5f175873d3ba5c54ef3a753dd06cc..5442f059a0df8388476a56ab8932c936216c6a48 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -24393,13 +24393,15 @@ class Window extends EventTarget implements WindowBase, WindowTimers native "Win
   @DocsEditable()
   final int screenY;
 
+  @JSName('scrollX')
   @DomName('Window.scrollX')
   @DocsEditable()
-  final int scrollX;
+  final int $dom_scrollX;
 
+  @JSName('scrollY')
   @DomName('Window.scrollY')
   @DocsEditable()
-  final int scrollY;
+  final int $dom_scrollY;
 
   @DomName('Window.scrollbars')
   @DocsEditable()
@@ -24966,6 +24968,11 @@ class Window extends EventTarget implements WindowBase, WindowTimers native "Win
   void moveTo(Point p) {
     $dom_moveTo(p.x, p.y);
   }
+
+  int get scrollX => JS('int', 
+      '#.scrollX || document.documentElement.scrollLeft', this);
+  int get scrollY => JS('int', 
+      '#.scrollY || document.documentElement.scrollTop', this);
 }
 
 /**