Add plugin info to the status page

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index a358c033cdb76cdf0b9f4f5a0b15585f20525aae..bad954c6c7ac1dccaaf732881d9474235c815967 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -20,6 +20,7 @@ import 'package:analysis_server/src/services/index/index.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/instrumentation/instrumentation.dart';
+import 'package:analyzer/plugin/plugin.dart';
 import 'package:analyzer/source/package_map_provider.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
@@ -234,6 +235,11 @@ class AnalysisServer {
   final ContentCache overlayState = new ContentCache();
 
   /**
+   * The plugins that are defined outside the analysis_server package.
+   */
+  List<Plugin> userDefinedPlugins;
+
+  /**
    * Initialize a newly created server to receive requests from and send
    * responses to the given [channel].
    *