Don't return private fields from imported libs

tools/ddbg.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Simple interactive debugger shell that connects to the Dart VM's debugger
 // connection port.
 
 #import("dart:io");
 #import("dart:json");
 
@@ skipping 23 matching lines @@
   so  Step over
   si  Step into
   sbp [<file>] <line> Set breakpoint
   rbp <id> Remove breakpoint with given id
   po <id> Print object info for given id
   pl <id> <idx> [<len>] Print list element/slice
   pc <id> Print class info for given id
   ll  List loaded libraries
   plib <id> Print library info for given library id
   pg <id> Print all global variables visible within given library id
-  ls <libname> List loaded scripts in library
+  ls <lib_id> List loaded scripts in library
   gs <lib_id> <script_url> Get source text of script in library
   epi <none|all|unhandled>  Set exception pause info
   h   Print help
 """);
 }
 
 
 void quitShell() {
   vmStream.close();
   vmSock.close();
@@ skipping 378 matching lines @@
   };
   vmInStream.onError = (err) {
     print("Error in debug connection: $err");
     quitShell();
   };
   vmInStream.onClosed = () {
     print("VM debugger connection closed");
     quitShell();
   };
 }