Fix type-check failure...

runtime/lib/mirrors_impl.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.
 
 // VM-specific implementation of the dart:mirrors library.
 
 // These values are allowed to be passed directly over the wire.
 bool isSimpleValue(var value) {
   return (value === null || value is num || value is String || value is bool);
 }
@@ skipping 83 matching lines @@
 
   // The IsolateMirror for the current isolate.
   static IsolateMirror localIsolateMirror() {
     if (_localIsolateMirror === null) {
       _localIsolateMirror = makeLocalIsolateMirror();
     }
     return _localIsolateMirror;
   }
 
   // Creates a new local IsolateMirror.
-  static bool makeLocalIsolateMirror()
+  static IsolateMirror makeLocalIsolateMirror()
       native 'Mirrors_makeLocalIsolateMirror';
 
   static Future<IsolateMirror> isolateMirrorOf(SendPort port) {
     Completer<IsolateMirror> completer = new Completer<IsolateMirror>();
     if (isLocalPort(port)) {
       // Make a local isolate mirror.
       completer.complete(localIsolateMirror());
     } else {
       // Make a remote isolate mirror.
       throw new NotImplementedException('Remote mirrors not yet implemented');
     }
     return completer.future;
   }
 }