DartWorkManager.getLibrariesContainingPart() should ask the ResultProvider for CONTAINING_LIBRARIES.

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

 // Copyright (c) 2015, 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 analyzer.src.task.dart_work_manager;
 
 import 'dart:collection';
 
 import 'package:analyzer/src/context/cache.dart';
 import 'package:analyzer/src/generated/engine.dart'
@@ skipping 184 matching lines @@
    * Maybe empty, but not null.
    */
   List<Source> getLibrariesContainingPart(Source part) {
     if (part.isInSystemLibrary) {
       DartWorkManager sdkDartWorkManager = _getSdkDartWorkManager();
       if (sdkDartWorkManager != this) {
         return sdkDartWorkManager.getLibrariesContainingPart(part);
       }
     }
     List<Source> libraries = partLibrariesMap[part];
+    libraries ??= _getLibrariesContainingPartFromResultProvider(part);
     return libraries?.toList() ?? Source.EMPTY_LIST;
   }
 
   @override
   TargetedResult getNextResult() {
     // Try to find a priority result to compute.
     while (priorityResultQueue.isNotEmpty) {
       TargetedResult result = priorityResultQueue.first;
       if (!_needsComputing(result.target, result.result)) {
         priorityResultQueue.remove(result);
@@ skipping 133 matching lines @@
         context.getNotice(source).setErrors(info.errors, info.lineInfo);
       }
     }
   }
 
   void unitIncrementallyResolved(Source librarySource, Source unitSource) {
     librarySourceQueue.add(librarySource);
   }
 
   /**
+   * Ask the [context]'s result provider for [CONTAINING_LIBRARIES].
+   * Return the list of containing libraries, or `null` if unknown.
+   */
+  List<Source> _getLibrariesContainingPartFromResultProvider(Source part) {
+    CacheEntry cacheEntry = context.getCacheEntry(part);
+    bool knows = context.aboutToComputeResult(cacheEntry, CONTAINING_LIBRARIES);
+    if (knows) {
+      return cacheEntry.getValue(CONTAINING_LIBRARIES);
+    }
+    return null;
+  }
+
+  /**
    * Return the SDK [DartWorkManager] or this one.
    */
   DartWorkManager _getSdkDartWorkManager() {
     SourceFactory sourceFactory = context.sourceFactory;
     InternalAnalysisContext sdkContext = sourceFactory.dartSdk.context;
     if (sdkContext != context) {
       for (WorkManager workManager in sdkContext.workManagers) {
         if (workManager is DartWorkManager) {
           return workManager;
         }
@@ skipping 105 matching lines @@
     }
   }
 
   bool _shouldErrorsBeComputed(Source source) =>
       context.shouldErrorsBeAnalyzed(source);
 
   static bool _isDartSource(AnalysisTarget target) {
     return target is Source && AnalysisEngine.isDartFileName(target.fullName);
   }
 }