Converted Observatory refs elements

runtime/observatory/tests/observatory_ui/mocks/repositories/instance.dart

 // Copyright (c) 2016, 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.
 
 part of mocks;
 
 typedef Future<M.Instance> InstanceRepositoryMockCallback(String id);
 
 class InstanceRepositoryMock implements M.InstanceRepository {
   final InstanceRepositoryMockCallback _get;
 
   InstanceRepositoryMock({InstanceRepositoryMockCallback getter})
     : _get = getter;
 
-  Future<M.Instance> get(String id){
+  Future<M.Instance> get(String id, {int count}){
     if (_get != null) {
       return _get(id);
     }
     return new Future.value(null);
   }
 }