Fix for DirectoryWatcher.handleError() closure signature.

pkg/analyzer/lib/file_system/physical_file_system.dart

Index: pkg/analyzer/lib/file_system/physical_file_system.dart
diff --git a/pkg/analyzer/lib/file_system/physical_file_system.dart b/pkg/analyzer/lib/file_system/physical_file_system.dart
index f3906be89b2ffff8c81dc929504dfe1bd9cfc848..f941252889b0a446a621eb165c3e9fc3df6e9ece 100644
--- a/pkg/analyzer/lib/file_system/physical_file_system.dart
+++ b/pkg/analyzer/lib/file_system/physical_file_system.dart
@@ -234,9 +234,9 @@ class _PhysicalFolder extends _PhysicalResource implements Folder {
   _PhysicalFolder(io.Directory directory) : super(directory);
 
   @override
-  Stream<WatchEvent> get changes => new DirectoryWatcher(_entry.path)
-      .events
-      .handleError(() {}, test: (error) => error is io.FileSystemException);
+  Stream<WatchEvent> get changes =>
+      new DirectoryWatcher(_entry.path).events.handleError((error) {},
+          test: (error) => error is io.FileSystemException);
 
   /**
    * Return the underlying file being represented by this wrapper.