Move the wire protocol support into the public API

pkg/analysis_server/test/plugin/set_analysis_domain_test.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 'dart:async';
 
 import 'package:analysis_server/plugin/analysis/analysis_domain.dart';
 import 'package:analysis_server/plugin/analysis/navigation/navigation.dart';
 import 'package:analysis_server/plugin/analysis/navigation/navigation_core.dart';
 import 'package:analysis_server/plugin/analysis/occurrences/occurrences.dart';
 import 'package:analysis_server/plugin/analysis/occurrences/occurrences_core.dart';
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/task/dart.dart';
 import 'package:plugin/plugin.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../analysis_abstract.dart';
 import '../utils.dart';
 
@@ skipping 131 matching lines @@
       expect(result.value, isNotNull);
       Source source = result.target.source;
       test.parsedUnitFiles.add(source.fullName);
       domain.scheduleNotification(
           result.context, source, AnalysisService.NAVIGATION);
       domain.scheduleNotification(
           result.context, source, AnalysisService.OCCURRENCES);
     });
   }
 }