Remove more references to the old plugin system

pkg/analysis_server/test/analysis_abstract.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_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart'
     hide AnalysisOptions;
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/domain_analysis.dart';
 import 'package:analysis_server/src/plugin/notification_manager.dart';
 import 'package:analysis_server/src/plugin/plugin_manager.dart';
 import 'package:analyzer/context/context_root.dart' as analyzer;
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/file_system/memory_file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
 import 'package:analyzer/src/dart/analysis/driver.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/sdk.dart';
 import 'package:analyzer_plugin/protocol/protocol.dart' as plugin;
 import 'package:analyzer_plugin/protocol/protocol_generated.dart' as plugin;
 import 'package:analyzer_plugin/src/protocol/protocol_internal.dart' as plugin;
 import 'package:plugin/manager.dart';
-import 'package:plugin/plugin.dart';
 import 'package:test/test.dart';
 import 'package:watcher/watcher.dart';
 
 import 'mock_sdk.dart';
 import 'mocks.dart';
 
 int findIdentifierLength(String search) {
   int length = 0;
   while (length < search.length) {
     int c = search.codeUnitAt(length);
@@ skipping 67 matching lines @@
   }
 
   String addTestFile(String content) {
     addFile(testFile, content);
     this.testCode = content;
     return testFile;
   }
 
   AnalysisServer createAnalysisServer() {
     //
-    // Collect plugins
-    //
-    List<Plugin> plugins = <Plugin>[];
-    plugins.addAll(AnalysisEngine.instance.requiredPlugins);
-    //
     // Process plugins
     //
     ExtensionManager manager = new ExtensionManager();
-    manager.processPlugins(plugins);
+    manager.processPlugins(AnalysisEngine.instance.requiredPlugins);
     //
     // Create an SDK in the mock file system.
     //
     new MockSdk(
         generateSummaryFiles: generateSummaryFiles,
         resourceProvider: resourceProvider);
     //
     // Create server
     //
     AnalysisServerOptions options = new AnalysisServerOptions();
@@ skipping 226 matching lines @@
       plugin.AnalysisUpdateContentParams params) {
     analysisUpdateContentParams = params;
   }
 
   @override
   Future<List<Null>> stopAll() async {
     fail('Unexpected invocation of stopAll');
     return null;
   }
 }