Adapt the existing incremental resolution implementation to the new model.

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

Index: pkg/analyzer/lib/src/task/dart_work_manager.dart
diff --git a/pkg/analyzer/lib/src/task/dart_work_manager.dart b/pkg/analyzer/lib/src/task/dart_work_manager.dart
index 06af9e94f5e2e530bf0cee9d5fd6d44b56cfc5f4..e006f86e5d0e11c8edf0f157b30d2d9f4c663881 100644
--- a/pkg/analyzer/lib/src/task/dart_work_manager.dart
+++ b/pkg/analyzer/lib/src/task/dart_work_manager.dart
@@ -242,6 +242,10 @@ class DartWorkManager implements WorkManager {
     return WorkOrderPriority.NONE;
   }
 
+  void unitIncrementallyResolved(Source librarySource, Source unitSource) {
+    librarySourceQueue.add(librarySource);
+  }
+
   @override
   void resultsComputed(
       AnalysisTarget target, Map<ResultDescriptor, dynamic> outputs) {