Remove the options plugin

pkg/analyzer/lib/plugin/options.dart

Index: pkg/analyzer/lib/plugin/options.dart
diff --git a/pkg/analyzer/lib/plugin/options.dart b/pkg/analyzer/lib/plugin/options.dart
index a2f7e1a9d2818417187d36b83ab53a7df3dcb21b..f884df5957781c3ddfb4a4165977ed81d4108a2e 100644
--- a/pkg/analyzer/lib/plugin/options.dart
+++ b/pkg/analyzer/lib/plugin/options.dart
@@ -7,17 +7,8 @@
 library analyzer.plugin.options;
 
 import 'package:analyzer/error/listener.dart';
-import 'package:analyzer/src/plugin/options_plugin.dart';
-import 'package:plugin/plugin.dart';
 import 'package:yaml/yaml.dart';
 
-/// The identifier of the extension point that allows plugins to validate
-/// options defined in the analysis options file. The object used as an
-/// extension must be an [OptionsValidator].
-final String OPTIONS_VALIDATOR_EXTENSION_POINT_ID = Plugin.join(
-    OptionsPlugin.UNIQUE_IDENTIFIER,
-    OptionsPlugin.OPTIONS_VALIDATOR_EXTENSION_POINT);
-
 /// Validates options as defined in an analysis options file.
 ///
 /// The options file format is intentionally very open-ended, giving clients