Revert "Use native async/await support in pub."

sdk/lib/_internal/pub_generated/lib/src/validator/directory.dart

Index: sdk/lib/_internal/pub_generated/lib/src/validator/directory.dart
diff --git a/sdk/lib/_internal/pub/lib/src/validator/directory.dart b/sdk/lib/_internal/pub_generated/lib/src/validator/directory.dart
similarity index 64%
copy from sdk/lib/_internal/pub/lib/src/validator/directory.dart
copy to sdk/lib/_internal/pub_generated/lib/src/validator/directory.dart
index 6039fc5c3b02f9be04a4568fe87e1bfab218d64c..a9935e8461d922d33c43ad0555a33b26d5ea9033 100644
--- a/sdk/lib/_internal/pub/lib/src/validator/directory.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/validator/directory.dart
@@ -15,11 +15,14 @@ import '../validator.dart';
 /// A validator that validates a package's top-level directories.
 class DirectoryValidator extends Validator {
   DirectoryValidator(Entrypoint entrypoint)
-    : super(entrypoint);
+      : super(entrypoint);
 
   static final _PLURAL_NAMES = [
-    "benchmarks", "docs", "examples", "tests", "tools"
-  ];
+      "benchmarks",
+      "docs",
+      "examples",
+      "tests",
+      "tools"];
 
   Future validate() {
     return new Future.sync(() {
@@ -30,17 +33,16 @@ class DirectoryValidator extends Validator {
         if (_PLURAL_NAMES.contains(dir)) {
           // Cut off the "s"
           var singularName = dir.substring(0, dir.length - 1);
-          warnings.add('Rename the top-level "$dir" directory to '
-                  '"$singularName".\n'
-              'The Pub layout convention is to use singular directory '
-                  'names.\n'
-              'Plural names won\'t be correctly identified by Pub and other '
-                  'tools.');
+          warnings.add(
+              'Rename the top-level "$dir" directory to ' '"$singularName".\n'
+                  'The Pub layout convention is to use singular directory ' 'names.\n'
+                  'Plural names won\'t be correctly identified by Pub and other ' 'tools.');
         }
 
         if (dir.contains(new RegExp(r"^samples?$"))) {
-          warnings.add('Rename the top-level "$dir" directory to "example".\n'
-              'This allows Pub to find your examples and create "packages" '
+          warnings.add(
+              'Rename the top-level "$dir" directory to "example".\n'
+                  'This allows Pub to find your examples and create "packages" '
                   'directories for them.\n');
         }
       }