Issue 22157. Cancel a pending refactoring request on receiving a new one.

pkg/analysis_server/test/mocks.dart

 // Copyright (c) 2014, 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.
 
 library mocks;
 
 @MirrorsUsed(targets: 'mocks', override: '*')
 import 'dart:mirrors';
 import 'dart:async';
 import 'dart:io';
@@ skipping 265 matching lines @@
   }
 
   Future<Response> waitForResponse(Request request) {
     String id = request.id;
     pumpEventQueue().then((_) {
       responseController.addError(new NoResponseException(request));
     });
     return responseController.stream.firstWhere((response) {
       return response.id == id;
     });
-//    return responseController.stream.firstWhere((response) {
-//      return response.id == id;
-//    });
   }
 }
 
 
 /**
  * A mock [ServerOperation] for testing [AnalysisServer].
  */
 class MockServerOperation implements PerformAnalysisOperation {
   final ServerOperationPriority priority;
   final MockServerOperationPerformFunction _perform;
@@ skipping 182 matching lines @@
     }
     return mismatchDescription;
   }
 
   @override
   bool matches(item, Map matchState) {
     Response response = item;
     return response != null && response.id == _id && response.error == null;
   }
 }