Clean-up the registration of plugins

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.
 
 library test.domain.analysis.abstract;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/analysis_server.dart';
@@ skipping 78 matching lines @@
 
   void addServerPlugins(List<Plugin> plugins) {}
 
   String addTestFile(String content) {
     addFile(testFile, content);
     this.testCode = content;
     return testFile;
   }
 
   AnalysisServer createAnalysisServer(Index index) {
+    //
+    // Collect plugins
+    //
     ServerPlugin serverPlugin = new ServerPlugin();
-    // TODO(pq): this convoluted extension registry dance needs cleanup.
-    List<Plugin> plugins = <Plugin>[
-      serverPlugin,
-      linterPlugin,
-      linterServerPlugin
-    ];
-    // Accessing `taskManager` ensures that AE plugins are registered.
-    AnalysisEngine.instance.taskManager;
+    List<Plugin> plugins = <Plugin>[];
     plugins.addAll(AnalysisEngine.instance.supportedPlugins);
+    plugins.add(serverPlugin);
+    plugins.add(linterPlugin);
+    plugins.add(linterServerPlugin);
     addServerPlugins(plugins);
-    // process plugins
+    //
+    // Process plugins
+    //
     ExtensionManager manager = new ExtensionManager();
     manager.processPlugins(plugins);
-    // create server
+    //
+    // Create server
+    //
     return new AnalysisServer(
         serverChannel,
         resourceProvider,
         packageMapProvider,
         index,
         serverPlugin,
         new AnalysisServerOptions(),
         new MockSdk(),
         InstrumentationService.NULL_SERVICE);
   }
@@ skipping 95 matching lines @@
   }
 
   /**
    * Completes with a successful [Response] for the given [request].
    * Otherwise fails.
    */
   Future<Response> waitResponse(Request request) async {
     return serverChannel.sendRequest(request);
   }
 }