Generate constants in server as we do in plugin

pkg/analysis_server/test/analysis_abstract.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.
 
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
     hide AnalysisOptions;
 import 'package:analysis_server/src/analysis_server.dart';
-import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/plugin/notification_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analysis_server/src/provisional/completion/dart/completion_plugin.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analyzer/context/context_root.dart' as analyzer;
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
@@ skipping 176 matching lines @@
   }
 
   String modifyTestFile(String content) {
     String path = resourceProvider.convertPath(testFile);
     resourceProvider.updateFile(path, content);
     this.testCode = content;
     return testFile;
   }
 
   void processNotification(Notification notification) {
-    if (notification.event == SERVER_ERROR) {
+    if (notification.event == SERVER_NOTIFICATION_ERROR) {
       var params = new ServerErrorParams.fromNotification(notification);
       serverErrors.add(params);
     }
   }
 
   void removeGeneralAnalysisSubscription(GeneralAnalysisService service) {
     generalServices.remove(service);
     Request request = new AnalysisSetGeneralSubscriptionsParams(generalServices)
         .toRequest('0');
     handleSuccessfulRequest(request);
@@ skipping 144 matching lines @@
   Future<List<Null>> stopAll() async {
     fail('Unexpected invocation of stopAll');
     return null;
   }
 
   @override
   void whitelistEverything() {
     fail('Unexpected invocation of whitelistEverything');
   }
 }