Initial task support

pkg/analyzer/test/src/task/test_support.dart

+// Copyright (c) 2015, 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.src.task.test_support;
+
+import 'package:analyzer/src/generated/engine.dart' hide AnalysisTask;
+import 'package:analyzer/task/model.dart';
+
+class TestAnalysisTask extends AnalysisTask {
+  TestAnalysisTask(AnalysisContext context, AnalysisTarget target) : super(context, target);
+
+  @override
+  String get description => 'Test task';
+
+  @override
+  internalPerform() {
+  }
+}