Fix for issue 21982

pkg/analyzer/lib/instrumentation/instrumentation.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 instrumentation;
 
 /**
  * The interface used by client code to communicate with an instrumentation
  * server.
  */
@@ skipping 27 matching lines @@
  * The interface used by client code to communicate with an instrumentation
  * server by wrapping an [InstrumentationServer].
  */
 class InstrumentationService {
   /**
    * An instrumentation service that will not log any instrumentation data.
    */
   static final InstrumentationService NULL_SERVICE =
       new InstrumentationService(null);
 
+  static const String TAG_ERROR = 'Err';
   static const String TAG_EXCEPTION = 'Ex';
   static const String TAG_NOTIFICATION = 'Noti';
   static const String TAG_REQUEST = 'Req';
   static const String TAG_RESPONSE = 'Res';
   static const String TAG_VERSION = 'Ver';
 
   /**
    * The instrumentation server used to communicate with the server, or `null`
    * if instrumentation data should not be logged.
    */
   InstrumentationServer _instrumentationServer;
 
   /**
    * Initialize a newly created instrumentation service to comunicate with the
    * given [instrumentationServer].
    */
   InstrumentationService(this._instrumentationServer);
 
   /**
    * The current time, expressed as a decimal encoded number of milliseconds.
    */
   String get _timestamp => new DateTime.now().millisecondsSinceEpoch.toString();
 
   /**
+   * Log the fact that an error, described by the given [message], has occurred.
+   */
+  void logError(String message) {
+    _log(TAG_ERROR, message);
+  }
+
+  /**
    * Log that the given non-priority [exception] was thrown, with the given
    * [stackTrace].
    */
   void logException(dynamic exception, StackTrace stackTrace) {
     if (_instrumentationServer != null) {
       String message = _toString(exception);
       String trace = _toString(stackTrace);
       _instrumentationServer.log('$_timestamp:$TAG_EXCEPTION:$message:$trace');
     }
   }
@@ skipping 56 matching lines @@
   /**
    * Convert the given [object] to a string.
    */
   String _toString(Object object) {
     if (object == null) {
       return 'null';
     }
     return object.toString();
   }
 }