Move the wire protocol support into the public API

pkg/analysis_server/test/analysis/notification_analyzedFiles_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.analysis.notification.analyzedDirectories;
 
 import 'dart:async';
 
+import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
-import 'package:analysis_server/src/protocol.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 import 'package:unittest/unittest.dart';
 
 import '../analysis_abstract.dart';
 import '../mocks.dart';
 import '../utils.dart';
 
 main() {
   initializeTestEnvironment();
   defineReflectiveTests(AnalysisNotificationAnalyzedFilesTest);
@@ skipping 89 matching lines @@
     await pumpEventQueue();
     await waitForTasksFinished();
     expect(analyzedFilesReceived, isTrue);
     assertHasFile('/foo.dart');
   }
 
   void unsubscribeAnalyzedFiles() {
     removeGeneralAnalysisSubscription(GeneralAnalysisService.ANALYZED_FILES);
   }
 }