Add Domain handler with startup and shutdown stubs

dart/pkg/analysis_server/lib/src/protocol.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 protocol;
 
 import 'dart:collection';
 import 'dart:convert';
 
 import 'package:analysis_server/src/computer/element.dart' show
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   /**
    * Attempt to handle the given [request]. If the request is not recognized by
    * this handler, return `null` so that other handlers will be given a chance
    * to handle it. Otherwise, return the response that should be passed back to
    * the client.
    */
   Response handleRequest(Request request);
 }
 
 /**
+ * Instances of the class [DomainHandler] implement a [RequestHandler] and
+ * also startup and shutdown methods.
+ */
+abstract class DomainHandler extends RequestHandler {
+  /**
+   * Perform any operations associated with the startup of the domain. This
+   * will be called before the first [Request].
+   */
+  void startup() { }
+
+  /**
+   * Perform any operations associated with the shutdown of the domain. It is
+   * not guaranteed that this method will be called. If it is, it will be
+   * called after the last [Request] has been made.
+   */
+  void shutdown() { }
+}
+
+/**
  * Instances of the class [Response] represent a response to a request.
  */
 class Response {
   /**
    * The [Response] instance that is returned when a real [Response] cannot
    * be provided at the moment.
    */
   static final Response DELAYED_RESPONSE = new Response('DELAYED_RESPONSE');
 
   /**
@@ skipping 186 matching lines @@
     hash = 0x1fffffff & (hash + ((0x03ffffff & hash) << 3));
     hash = hash ^ (hash >> 11);
     return 0x1fffffff & (hash + ((0x00003fff & hash) << 15));
   }
 
   static int hash2(a, b) => finish(combine(combine(0, a), b));
 
   static int hash4(a, b, c, d) =>
       finish(combine(combine(combine(combine(0, a), b), c), d));
 }