Add AnalysisContext.onResultInvalidated(descriptor).

pkg/analyzer/lib/src/task/options_work_manager.dart

Index: pkg/analyzer/lib/src/task/options_work_manager.dart
diff --git a/pkg/analyzer/lib/src/task/options_work_manager.dart b/pkg/analyzer/lib/src/task/options_work_manager.dart
index 4447f30193bf286bf5a93b0ce3361095b37bf1fe..ec5e9928310b6fba6bcdd80930191f2698740e91 100644
--- a/pkg/analyzer/lib/src/task/options_work_manager.dart
+++ b/pkg/analyzer/lib/src/task/options_work_manager.dart
@@ -7,14 +7,7 @@ library analyzer.src.task.options_work_manager;
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
-import 'package:analyzer/src/generated/engine.dart'
-    show
-        AnalysisEngine,
-        AnalysisErrorInfo,
-        AnalysisErrorInfoImpl,
-        AnalysisOptions,
-        CacheState,
-        InternalAnalysisContext;
+import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/error.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/task/options.dart';
@@ -169,6 +162,7 @@ class OptionsWorkManager implements WorkManager {
   }
 
   /// Return `true` if the given target is an `.analysis_options` source.
-  static bool _isOptionsSource(AnalysisTarget target) => target is Source &&
+  static bool _isOptionsSource(AnalysisTarget target) =>
+      target is Source &&
       AnalysisEngine.isAnalysisOptionsFileName(target.fullName);
 }