Add timestamps to integration test output.

pkg/analysis_server/test/integration/integration_tests.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.integration.analysis;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 499 matching lines @@
    * True if we are currently printing out messages exchanged with the server.
    */
   bool _debuggingStdio = false;
 
   /**
    * True if we've received bad data from the server, and we are aborting the
    * test.
    */
   bool _receivedBadDataFromServer = false;
 
-  Server._(this._process);
+  /**
+   * Stopwatch that we use to generate timing information for debug output.
+   */
+  Stopwatch _time = new Stopwatch();
+
+  Server._(this._process) {
+    _time.start();
+  }
 
   /**
    * Get a stream which will receive notifications of the given event type.
    * The values delivered to the stream will be the contents of the 'params'
    * field of the notification message.
    */
   Stream onNotification(String event) {
     Stream notificationStream = _notificationStreams[event];
     if (notificationStream == null) {
       StreamController notificationController = new StreamController();
@@ skipping 164 matching lines @@
     new Future.delayed(new Duration(seconds: 1), expectAsync(() {
       fail('Bad data received from server');
     }));
   }
 
   /**
    * Record a message that was exchanged with the server, and print it out if
    * [debugStdio] has been called.
    */
   void _recordStdio(String line) {
+    double elapsedTime = _time.elapsedTicks.toDouble() /
+        _time.frequency.toDouble();

[scheglov, 2014/07/30 18:46:15]

Do you need toDouble() here?
3 / 2 already gives 1.5

+    line = "$elapsedTime: $line";
     if (_debuggingStdio) {
       print(line);
     }
     _recordedStdio.add(line);
   }
 }