Use native async/await support in pub.

sdk/lib/_internal/pub_generated/test/run/displays_transformer_logs_test.dart

-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import '../descriptor.dart' as d;
-import '../test_pub.dart';
-
-const SCRIPT = """
-import "package:myapp/lib.dart";
-main() {
-  callLib();
-}
-""";
-
-const LIB = """
-callLib() {
-  print("lib");
-}
-""";
-
-// Make it lazy so that "lib.dart" isn't transformed until after the process
-// is started. Otherwise, since this tranformer modifies .dart files, it will
-// be run while the transformers themselves are loading during pub run's
-// startup.
-const TRANSFORMER = """
-import 'dart:async';
-
-import 'package:barback/barback.dart';
-
-class LoggingTransformer extends Transformer implements LazyTransformer {
-  LoggingTransformer.asPlugin();
-
-  String get allowedExtensions => '.dart';
-
-  void apply(Transform transform) {
-    transform.logger.info('\${transform.primaryInput.id}.');
-    transform.logger.warning('\${transform.primaryInput.id}.');
-  }
-
-  void declareOutputs(DeclaringTransform transform) {
-    // TODO(rnystrom): Remove this when #19408 is fixed.
-    transform.declareOutput(transform.primaryId);
-  }
-}
-""";
-
-main() {
-  initConfig();
-  withBarbackVersions("any", () {
-    integration('displays transformer log messages', () {
-      d.dir(appPath, [d.pubspec({
-          "name": "myapp",
-          "transformers": ["myapp/src/transformer"]
-        }),
-            d.dir(
-                "lib",
-                [
-                    d.file("lib.dart", LIB),
-                    d.dir("src", [d.file("transformer.dart", TRANSFORMER)])]),
-            d.dir("bin", [d.file("script.dart", SCRIPT)])]).create();
-
-      createLockFile('myapp', pkg: ['barback']);
-
-      var pub = pubRun(args: ["script"]);
-
-      // Note that the info log is only displayed here because the test
-      // harness runs pub in verbose mode. By default, only the warning would
-      // be shown.
-      pub.stdout.expect("[Info from Logging]:");
-      pub.stdout.expect("myapp|bin/script.dart.");
-
-      pub.stderr.expect("[Warning from Logging]:");
-      pub.stderr.expect("myapp|bin/script.dart.");
-
-      pub.stdout.expect("[Info from Logging]:");
-      pub.stdout.expect("myapp|lib/lib.dart.");
-
-      pub.stderr.expect("[Warning from Logging]:");
-      pub.stderr.expect("myapp|lib/lib.dart.");
-
-      pub.stdout.expect("lib");
-      pub.shouldExit();
-    });
-  });
-}