move context id constant to AnalysisServer

pkg/analysis_server/lib/src/analysis_server.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 analysis.server;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_logger.dart';
 import 'package:analysis_server/src/channel.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/java_core.dart';
 
 /**
  * Instances of the class [AnalysisServer] implement a server that listens on a
  * [CommunicationChannel] for analysis requests and process them.
  */
 class AnalysisServer {
   /**
    * The name of the notification of new errors associated with a source.
    */
   static const String ERROR_NOTIFICATION_NAME = 'context.errors';
 
   /**
+   * The name of the contextId parameter.
+   */
+  static const String CONTEXT_ID_PARAM = 'contextId';
+
+  /**
    * The name of the parameter whose value is a list of errors.
    */
   static const String ERRORS_PARAM = 'errors';
 
   /**
    * The name of the parameter whose value is a source.
    */
   static const String SOURCE_PARAM = 'source';
 
   /**
@@ skipping 184 matching lines @@
   void sendNotification(Notification notification) {
     channel.sendNotification(notification);
   }
 
   void _scheduleTask() {
     new Future(performTask).catchError((ex, st) {
       AnalysisEngine.instance.logger.logError("${ex}\n${st}");
     });
   }
 }