Create default tasks if plugins are not being used

pkg/analyzer/lib/src/generated/engine.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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine;
 
-import "dart:math" as math;
 import 'dart:async';
 import 'dart:collection';
+import 'dart:math' as math;
 
 import 'package:analyzer/src/cancelable_future.dart';
 import 'package:analyzer/src/context/cache.dart' as cache;
 import 'package:analyzer/src/context/context.dart' as newContext;
 import 'package:analyzer/src/generated/incremental_resolution_validator.dart';
 import 'package:analyzer/src/plugin/engine_plugin.dart';
 import 'package:analyzer/src/services/lint.dart';
 import 'package:analyzer/src/task/manager.dart';
 import 'package:analyzer/src/task/task_dart.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:analyzer/task/model.dart';
+import 'package:plugin/manager.dart';
 
 import '../../instrumentation/instrumentation.dart';
 import 'ast.dart';
 import 'constant.dart';
 import 'element.dart';
 import 'error.dart';
 import 'error_verifier.dart';
 import 'html.dart' as ht;
 import 'incremental_resolver.dart'
     show IncrementalResolver, PoorMansIncrementalResolver;
@@ skipping 5728 matching lines @@
    */
   void set logger(Logger logger) {
     this._logger = logger == null ? Logger.NULL : logger;
   }
 
   /**
    * Return the task manager used to manage the tasks used to analyze code.
    */
   TaskManager get taskManager {
     if (_taskManager == null) {
+      if (enginePlugin.taskExtensionPoint == null) {
+        // The plugin wasn't used, so tasks are not registered.
+        new ExtensionManager().processPlugins([enginePlugin]);
+      }
       _taskManager = new TaskManager();
       _taskManager.addTaskDescriptors(enginePlugin.taskDescriptors);
       // TODO(brianwilkerson) Create a way to associate different results with
       // different file suffixes, then make this pluggable.
       _taskManager.addGeneralResult(DART_ERRORS);
     }
     return _taskManager;
   }
 
   /**
@@ skipping 5904 matching lines @@
     PendingFuture pendingFuture =
         new PendingFuture<T>(_context, source, computeValue);
     if (!pendingFuture.evaluate(sourceEntry)) {
       _context._pendingFutureSources
           .putIfAbsent(source, () => <PendingFuture>[])
           .add(pendingFuture);
     }
     return pendingFuture.future;
   }
 }