Report plugin errors to the instrumentation service

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 analyzer.instrumentation.instrumentation;
 
 import 'dart:async';
 import 'dart:convert';
 
 import 'package:analyzer/task/model.dart';
@@ skipping 195 matching lines @@
           .log(_join([TAG_PERFORMANCE, kind, elapsed, message]));
     }
   }
 
   /**
    * Log the fact that an error, described by the given [message], was reported
    * by the given [plugin].
    */
   void logPluginError(
       PluginData plugin, String code, String message, String stackTrace) {
-    List<String> fields = <String>[TAG_PLUGIN_ERROR, code, message, stackTrace];
-    plugin.addToFields(fields);
-    _instrumentationServer.log(_join(fields));
+    if (_instrumentationServer != null) {
+      List<String> fields = <String>[
+        TAG_PLUGIN_ERROR,
+        code,
+        message,
+        stackTrace
+      ];
+      plugin.addToFields(fields);
+      _instrumentationServer.log(_join(fields));
+    }
   }
 
   /**
    * Log that the given non-priority [exception] was thrown, with the given
    * [stackTrace] by the given [plugin].
    */
   void logPluginException(
       PluginData plugin, dynamic exception, StackTrace stackTrace) {
     if (_instrumentationServer != null) {
       List<String> fields = <String>[
@@ skipping 272 matching lines @@
   /**
    * Add the information about the plugin to the list of [fields] to be sent to
    * the instrumentation server.
    */
   void addToFields(List<String> fields) {
     fields.add(pluginId);
     fields.add(name ?? '');
     fields.add(version ?? '');
   }
 }