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

sdk/lib/_internal/pub_generated/lib/src/cached_package.dart

Index: sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/cached_package.dart b/sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
deleted file mode 100644
index 1e1c595e8d6ca1a01b40130a5f5994e71a670a21..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/cached_package.dart
+++ /dev/null
@@ -1,88 +0,0 @@
-// 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.
-
-library pub.cached_package;
-
-import 'package:path/path.dart' as p;
-import 'package:pub_semver/pub_semver.dart';
-import 'package:yaml/yaml.dart';
-
-import 'barback/transformer_config.dart';
-import 'io.dart';
-import 'package.dart';
-import 'pubspec.dart';
-
-/// A [Package] whose `lib` directory has been precompiled and cached.
-///
-/// When users of this class request path information about files that are
-/// cached, this returns the cached information. It also wraps the package's
-/// pubspec to report no transformers, since the transformations have all been
-/// applied already.
-class CachedPackage extends Package {
-  /// The directory contianing the cached assets from this package.
-  ///
-  /// Although only `lib` is cached, this directory corresponds to the root of
-  /// the package. The actual cached assets exist in `$_cacheDir/lib`.
-  final String _cacheDir;
-
-  /// Creates a new cached package wrapping [inner] with the cache at
-  /// [_cacheDir].
-  CachedPackage(Package inner, this._cacheDir)
-      : super(new _CachedPubspec(inner.pubspec), inner.dir);
-
-  String path(String part1, [String part2, String part3, String part4,
-      String part5, String part6, String part7]) {
-    if (_pathInCache(part1)) {
-      return p.join(_cacheDir, part1, part2, part3, part4, part5, part6, part7);
-    } else {
-      return super.path(part1, part2, part3, part4, part5, part6, part7);
-    }
-  }
-
-  String relative(String path) {
-    if (p.isWithin(path, _cacheDir)) return p.relative(path, from: _cacheDir);
-    return super.relative(path);
-  }
-
-  /// This will include the cached, transformed versions of files if [beneath]
-  /// is within a cached directory, but not otherwise.
-  List<String> listFiles({String beneath, recursive: true, bool useGitIgnore:
-      false}) {
-    if (beneath == null) {
-      return super.listFiles(recursive: recursive, useGitIgnore: useGitIgnore);
-    }
-
-    if (_pathInCache(beneath)) return listDir(p.join(_cacheDir, beneath));
-    return super.listFiles(
-        beneath: beneath,
-        recursive: recursive,
-        useGitIgnore: useGitIgnore);
-  }
-
-  /// Returns whether [relativePath], a path relative to the package's root,
-  /// is in a cached directory.
-  bool _pathInCache(String relativePath) => p.isWithin('lib', relativePath);
-}
-
-/// A pubspec wrapper that reports no transformers.
-class _CachedPubspec implements Pubspec {
-  final Pubspec _inner;
-
-  YamlMap get fields => _inner.fields;
-  String get name => _inner.name;
-  Version get version => _inner.version;
-  List<PackageDep> get dependencies => _inner.dependencies;
-  List<PackageDep> get devDependencies => _inner.devDependencies;
-  List<PackageDep> get dependencyOverrides => _inner.dependencyOverrides;
-  PubspecEnvironment get environment => _inner.environment;
-  String get publishTo => _inner.publishTo;
-  Map<String, String> get executables => _inner.executables;
-  bool get isPrivate => _inner.isPrivate;
-  bool get isEmpty => _inner.isEmpty;
-  List<PubspecException> get allErrors => _inner.allErrors;
-
-  List<Set<TransformerConfig>> get transformers => const [];
-
-  _CachedPubspec(this._inner);
-}