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

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

Index: sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart b/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
deleted file mode 100644
index 739a7d7433621da4a9904598e45226ba16cdd7d1..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/package_graph.dart
+++ /dev/null
@@ -1,120 +0,0 @@
-// Copyright (c) 2013, 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.package_graph;
-
-import 'barback/transformer_cache.dart';
-import 'entrypoint.dart';
-import 'lock_file.dart';
-import 'package.dart';
-import 'source/cached.dart';
-import 'utils.dart';
-
-/// A holistic view of the entire transitive dependency graph for an entrypoint.
-///
-/// A package graph can be loaded using [Entrypoint.loadPackageGraph].
-class PackageGraph {
-  /// The entrypoint.
-  final Entrypoint entrypoint;
-
-  /// The entrypoint's lockfile.
-  ///
-  /// This describes the sources and resolved descriptions of everything in
-  /// [packages].
-  final LockFile lockFile;
-
-  /// The transitive dependencies of the entrypoint (including itself).
-  ///
-  /// This may not include all transitive dependencies of the entrypoint if the
-  /// creator of the package graph knows only a subset of the packages are
-  /// relevant in the current context.
-  final Map<String, Package> packages;
-
-  /// A map of transitive dependencies for each package.
-  Map<String, Set<Package>> _transitiveDependencies;
-
-  /// The transformer cache, if it's been loaded.
-  TransformerCache _transformerCache;
-
-  PackageGraph(this.entrypoint, this.lockFile, this.packages);
-
-  /// Loads the transformer cache for this graph.
-  ///
-  /// This may only be called if [entrypoint] represents a physical package.
-  /// This may modify the cache.
-  TransformerCache loadTransformerCache() {
-    if (_transformerCache == null) {
-      if (entrypoint.root.dir == null) {
-        throw new StateError(
-            "Can't load the transformer cache for virtual "
-                "entrypoint ${entrypoint.root.name}.");
-      }
-      _transformerCache = new TransformerCache.load(this);
-    }
-    return _transformerCache;
-  }
-
-  /// Returns all transitive dependencies of [package].
-  ///
-  /// For the entrypoint this returns all packages in [packages], which includes
-  /// dev and override. For any other package, it ignores dev and override
-  /// dependencies.
-  Set<Package> transitiveDependencies(String package) {
-    if (package == entrypoint.root.name) return packages.values.toSet();
-
-    if (_transitiveDependencies == null) {
-      var closure = transitiveClosure(
-          mapMap(
-              packages,
-              value: (_, package) => package.dependencies.map((dep) => dep.name)));
-      _transitiveDependencies = mapMap(
-          closure,
-          value: (_, names) => names.map((name) => packages[name]).toSet());
-    }
-
-    return _transitiveDependencies[package];
-  }
-
-  /// Returns whether [package] is mutable.
-  ///
-  /// A package is considered to be mutable if it or any of its dependencies
-  /// don't come from a cached source, since the user can change its contents
-  /// without modifying the pub cache. Information generated from mutable
-  /// packages is generally not safe to cache, since it may change frequently.
-  bool isPackageMutable(String package) {
-    var id = lockFile.packages[package];
-    if (id == null) return true;
-
-    var source = entrypoint.cache.sources[id.source];
-    if (source is! CachedSource) return true;
-
-    return transitiveDependencies(package).any((dep) {
-      var depId = lockFile.packages[dep.name];
-
-      // The entrypoint package doesn't have a lockfile entry. It's always
-      // mutable.
-      if (depId == null) return true;
-
-      return entrypoint.cache.sources[depId.source] is! CachedSource;
-    });
-  }
-
-  /// Returns whether [package] is static.
-  ///
-  /// A package is considered to be static if it's not transformed and it came
-  /// from a cached source. Static packages don't need to be fully processed by
-  /// barback.
-  ///
-  /// Note that a static package isn't the same as an immutable package (see
-  /// [isPackageMutable]).
-  bool isPackageStatic(String package) {
-    var id = lockFile.packages[package];
-    if (id == null) return false;
-
-    var source = entrypoint.cache.sources[id.source];
-    if (source is! CachedSource) return false;
-
-    return packages[package].pubspec.transformers.isEmpty;
-  }
-}