Make server use the common protocol classes

pkg/analysis_server/test/search/abstract_search_domain.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_generated.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/search/search_domain.dart';
 import 'package:analysis_server/src/services/index/index.dart'
     show Index, createMemoryIndex;
+import 'package:analyzer_plugin/protocol/protocol_common.dart';
 import 'package:test/test.dart';
 
 import '../analysis_abstract.dart';
 
 class AbstractSearchDomainTest extends AbstractAnalysisTest {
   final Map<String, _ResultSet> resultSets = {};
   String searchId;
   List<SearchResult> results = <SearchResult>[];
   SearchResult result;
 
@@ skipping 87 matching lines @@
   }
 }
 
 class _ResultSet {
   final String id;
   final List<SearchResult> results = <SearchResult>[];
   bool done = false;
 
   _ResultSet(this.id);
 }