Do not use overloaded toDartValue for bindings classes.

lib/dom/idl/dart/dart.idl

 
 // This file introduces / supplements and forces Dart declarations.
 
 module default {
   NamedNodeMap implements sequence<Node>;
   NodeList implements sequence<Node>;
   HTMLCollection implements sequence<Node>;
   MediaList implements sequence<DOMString>;
   StyleSheetList implements sequence<StyleSheet>;
   TouchList implements sequence<Touch>;
@@ skipping 212 matching lines @@
   interface IDBKeyRange {
     [Suppressed] static IDBKeyRange only(in IDBKey value)
         raises (IDBDatabaseException);
     [Suppressed] static IDBKeyRange lowerBound(in IDBKey bound, in optional boolean open)
         raises (IDBDatabaseException);
     [Suppressed] static IDBKeyRange upperBound(in IDBKey bound, in optional boolean open)
         raises (IDBDatabaseException);
     [Suppressed] static IDBKeyRange bound(in IDBKey lower, in IDBKey upper, in optional boolean lowerOpen, optional boolean upperOpen)
         raises (IDBDatabaseException);
   };
+
+  interface EntrySync {
+    // Native implementation is declared to return EntrySync.
+    [Suppressed] DirectoryEntrySync getParent();
+    EntrySync getParent();
+  };
 };
 
 module html {
   [Supplemental, Callback] // Add missing Callback attribute.
   interface VoidCallback {
   };
 };
 
 module svg {
     interface SVGNumber {
       [StrictTypeChecking, Custom] attribute double value;
     };
 }