Make AnalysisServer.onAnalysisComplete a Future and wait for it before refactoring.

pkg/analysis_server/test/analysis_abstract.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 test.domain.analysis.abstract;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
@@ skipping 240 matching lines @@
 
   void tearDown() {
     server.done();
     handler = null;
     server = null;
     resourceProvider = null;
     serverChannel = null;
   }
 
   /**
-   * Returns a [Future] that completes when the [AnalysisServer] finishes
-   * all its scheduled tasks.
+   * Returns a [Future] that completes when the server's analysis is complete.
    */
   Future waitForTasksFinished() {
-    return waitForServerOperationsPerformed(server);
+    return server.onAnalysisComplete;
   }
 }