Fix indexed access for DataTransferItemList

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index e2a3272542fca5446559b857eee55b73cbfbd0d9..db10d1eef14e6647a93ccccfacd8227e39a05a8f 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -9495,7 +9495,10 @@ class DataTransferItemList extends DartHtmlDomObject {
   
 
   DataTransferItem operator[] (int index) {
-    return __getter__(index);
+    // TODO(alanknight): I think that all the __getter__ generators should just
+    // do property access, but that's major surgery. This one is a problem, so
+    // just hard-code it for now.
+    return _blink.Blink_JsNative_DomException.getProperty(unwrap_jso(this), index);
   }
 
 }