Clean-up the registration of plugins

pkg/analysis_server/test/domain_diagnostic_test.dart

Index: pkg/analysis_server/test/domain_diagnostic_test.dart
diff --git a/pkg/analysis_server/test/domain_diagnostic_test.dart b/pkg/analysis_server/test/domain_diagnostic_test.dart
index 444e6cffddd12368987fea49c6c1c4f662276534..0e8fd2ad91835275417d71439d01ccf2b55e6347 100644
--- a/pkg/analysis_server/test/domain_diagnostic_test.dart
+++ b/pkg/analysis_server/test/domain_diagnostic_test.dart
@@ -10,7 +10,9 @@ import 'package:analysis_server/src/domain_diagnostic.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/engine.dart';
 import 'package:plugin/manager.dart';
+import 'package:plugin/plugin.dart';
 import 'package:unittest/unittest.dart';
 
 import 'mock_sdk.dart';
@@ -25,11 +27,25 @@ main() {
   initializeTestEnvironment();
 
   setUp(() {
+    //
+    // Collect plugins
+    //
+    ServerPlugin serverPlugin = new ServerPlugin();
+    List<Plugin> plugins = <Plugin>[];
+    plugins.addAll(AnalysisEngine.instance.requiredPlugins);
+    plugins.add(AnalysisEngine.instance.commandLinePlugin);
+    plugins.add(AnalysisEngine.instance.optionsPlugin);
+    plugins.add(serverPlugin);
+    //
+    // Process plugins
+    //
+    ExtensionManager manager = new ExtensionManager();
+    manager.processPlugins(plugins);
+    //
+    // Create the server
+    //
     var serverChannel = new MockServerChannel();
     resourceProvider = new MemoryResourceProvider();
-    ExtensionManager manager = new ExtensionManager();
-    ServerPlugin serverPlugin = new ServerPlugin();
-    manager.processPlugins([serverPlugin]);
     server = new AnalysisServer(
         serverChannel,
         resourceProvider,