Remove uses of the old plugin model from the analysis server

pkg/analysis_server/test/domain_server_test.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 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/domain_server.dart';
-import 'package:analysis_server/src/plugin/server_plugin.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/src/generated/sdk.dart';
-import 'package:plugin/manager.dart';
 import 'package:test/test.dart';
 
 import 'mocks.dart';
 
 main() {
   AnalysisServer server;
   ServerDomainHandler handler;
   MockServerChannel serverChannel;
 
   setUp(() {
     serverChannel = new MockServerChannel();
     var resourceProvider = new MemoryResourceProvider();
-    ExtensionManager manager = new ExtensionManager();
-    ServerPlugin serverPlugin = new ServerPlugin();
-    manager.processPlugins([serverPlugin]);
     server = new AnalysisServer(
         serverChannel,
         resourceProvider,
         new MockPackageMapProvider(),
-        serverPlugin,
         new AnalysisServerOptions(),
         new DartSdkManager('', false),
         InstrumentationService.NULL_SERVICE);
     handler = new ServerDomainHandler(server);
   });
 
   group('ServerDomainHandler', () {
     test('getVersion', () {
       var request = new ServerGetVersionParams().toRequest('0');
       var response = handler.handleRequest(request);
@@ skipping 32 matching lines @@
       // send request
       var request = new ServerShutdownParams().toRequest('0');
       var response = await serverChannel.sendRequest(request);
       expect(response, isResponseSuccess('0'));
 
       // server is down
       expect(server.running, isFalse);
     });
   });
 }