Another dartium fix. I swear this is the last one.

lib/html/release/html.dart

Index: lib/html/release/html.dart
diff --git a/lib/html/release/html.dart b/lib/html/release/html.dart
index fc79422f9757cb7d89d8963fed49791ba45568fe..07f96dfe885eecebdcde9af02ab31ef230fd002f 100644
--- a/lib/html/release/html.dart
+++ b/lib/html/release/html.dart
@@ -6773,7 +6773,7 @@ class _DocumentImpl extends _NodeImpl
   _DocumentImpl._wrap(ptr) : super._wrap(ptr);
 
   _DocumentEventsImpl get on() {
-    if (_on == null) _on = new _DocumentEventsImpl(_wrappedDocumentPtr);
+    if (_on == null) _on = new _DocumentEventsImpl(this);
     return _on;
   }
 
@@ -20969,7 +20969,7 @@ class _WheelEventImpl extends _UIEventImpl implements WheelEvent {
 
 class _WindowImpl extends _EventTargetImpl implements Window {
 
-  _DocumentImpl get document() => _wrap(_ptr.document.documentElement);
+  _DocumentImpl get document() => _wrap(_ptr.document);
 
   void requestLayoutFrame(TimeoutHandler callback) {
     _addMeasurementFrameCallback(callback);