recompute package map when input file changes

pkg/analyzer/lib/file_system/memory_file_system.dart

Index: pkg/analyzer/lib/file_system/memory_file_system.dart
diff --git a/pkg/analyzer/lib/file_system/memory_file_system.dart b/pkg/analyzer/lib/file_system/memory_file_system.dart
index d85a224da8aad03c23f9965f05269e79ad956e9f..a68a2259fe05e049731d43e5ee218ee6dc4922fc 100644
--- a/pkg/analyzer/lib/file_system/memory_file_system.dart
+++ b/pkg/analyzer/lib/file_system/memory_file_system.dart
@@ -164,7 +164,7 @@ class MemoryResourceProvider implements ResourceProvider {
   void _notifyWatchers(String path, ChangeType changeType) {
     _pathToWatchers.forEach((String watcherPath,
         List<StreamController<WatchEvent>> streamControllers) {
-      if (posix.isWithin(watcherPath, path)) {
+      if (watcherPath == path || posix.isWithin(watcherPath, path)) {
         for (StreamController<WatchEvent> streamController
             in streamControllers) {
           streamController.add(new WatchEvent(changeType, path));