Extract protocol_dart.dart APIs.

pkg/analysis_server/test/plugin/test_all.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.plugin.analysis_contributor;
 
 import 'package:unittest/unittest.dart';
 
 import '../utils.dart';
+import 'protocol_dart_test.dart' as protocol_dart_test;
 import 'set_analysis_domain_test.dart' as set_analysis_domain_test;
 
 /**
  * Utility for manually running all tests.
  */
 main() {
   initializeTestEnvironment();
   group('plugin', () {
+    protocol_dart_test.main();
     set_analysis_domain_test.main();
   });
 }