Use precompiled dependencies in pub.

sdk/lib/_internal/pub/lib/src/validator/license.dart

Index: sdk/lib/_internal/pub/lib/src/validator/license.dart
diff --git a/sdk/lib/_internal/pub/lib/src/validator/license.dart b/sdk/lib/_internal/pub/lib/src/validator/license.dart
index 6ac2875d63a5954e407f8f8a358144d7ce8bcc7e..46ca112cb76ed1a628f9b753245cf2c632bbbf15 100644
--- a/sdk/lib/_internal/pub/lib/src/validator/license.dart
+++ b/sdk/lib/_internal/pub/lib/src/validator/license.dart
@@ -9,7 +9,6 @@ import 'dart:async';
 import 'package:path/path.dart' as path;
 
 import '../entrypoint.dart';
-import '../io.dart';
 import '../utils.dart';
 import '../validator.dart';
 
@@ -22,7 +21,7 @@ class LicenseValidator extends Validator {
     return new Future.sync(() {
       var licenseLike = new RegExp(
           r"^([a-zA-Z0-9]+[-_])?(LICENSE|COPYING)(\..*)?$");
-      if (listDir(entrypoint.root.dir)
+      if (entrypoint.root.listFiles(recursive: false)
           .map(path.basename)
           .any(licenseLike.hasMatch)) {
         return;