Use pub list-package-dirs in analyzer command line

pkg/analysis_server/lib/src/socket_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 socket.server;
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/domain_completion.dart';
 import 'package:analysis_server/src/edit/edit_domain.dart';
 import 'package:analysis_server/src/search/search_domain.dart';
 import 'package:analysis_server/src/domain_server.dart';
-import 'package:analysis_server/src/package_map_provider.dart';
+import 'package:analyzer/source/package_map_provider.dart';
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analyzer/file_system/physical_file_system.dart';
 import 'package:analyzer/src/generated/sdk_io.dart';
 import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/index/local_file_index.dart';
 import 'package:analysis_server/src/domain_execution.dart';
 
 
 /**
  * Creates and runs an [Index].
@@ skipping 54 matching lines @@
     server.handlers = [
         new ServerDomainHandler(server),
         new AnalysisDomainHandler(server),
         new EditDomainHandler(server),
         new SearchDomainHandler(server),
         new CompletionDomainHandler(server),
         new ExecutionDomainHandler(server),
     ];
   }
 }