Fix comments in benchmark

pkg/analysis_server/benchmark/perf/memory_tests.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.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 80 matching lines @@
    */
   ProcessResult _run(String executable, List<String> arguments) {
     return Process.runSync(executable, arguments,
         stderrEncoding: UTF8, stdoutEncoding: UTF8);
   }
 
   /**
    *  1. Start Analysis Server.
    *  2. Set the analysis [roots].
    *  3. Wait for analysis to complete.
-   *  4. Record the time to finish analysis.
+   *  4. Record the heap size after analysis is finished.
    *  5. Shutdown.
    *  6. Go to (1).
    */
   static Future<List<int>> start_waitInitialAnalysis_shutdown(
       {List<String> roots, int numOfRepeats}) async {
     expect(roots, isNotNull, reason: 'roots');
     expect(numOfRepeats, isNotNull, reason: 'numOfRepeats');
     // Repeat.
     List<int> sizes = <int>[];
     for (int i = 0; i < numOfRepeats; i++) {
       AnalysisServerMemoryUsageTest test = new AnalysisServerMemoryUsageTest();
       // Initialize Analysis Server.
       await test.setUp();
       await test.subscribeToStatusNotifications();
       // Set roots and analyze.
       await test.sendAnalysisSetAnalysisRoots(roots, []);
       await test.analysisFinished;
       sizes.add(test.getMemoryUsage());
       // Stop the server.
       await test.shutdown();
     }
     return sizes;
   }
 }