Do not use overloaded toDartValue for bindings classes.

lib/dom/idl/dart/dart.idl

Index: lib/dom/idl/dart/dart.idl
diff --git a/lib/dom/idl/dart/dart.idl b/lib/dom/idl/dart/dart.idl
index e356caa833e9ea03abdf8c8713f48becac605f9c..9dfefe8529b01370d9d00adad2cbfd2ffdb5e3d0 100644
--- a/lib/dom/idl/dart/dart.idl
+++ b/lib/dom/idl/dart/dart.idl
@@ -230,6 +230,12 @@ module storage {
     [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 {