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

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

Index: sdk/lib/_internal/pub_generated/lib/src/lock_file.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/lock_file.dart b/sdk/lib/_internal/pub_generated/lib/src/lock_file.dart
deleted file mode 100644
index fa964c70f803c727c63f53ef171d8ed8ff06630f..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/pub_generated/lib/src/lock_file.dart
+++ /dev/null
@@ -1,147 +0,0 @@
-// Copyright (c) 2012, 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.lock_file;
-
-import 'package:path/path.dart' as p;
-import 'package:pub_semver/pub_semver.dart';
-import 'package:source_span/source_span.dart';
-import 'package:yaml/yaml.dart';
-
-import 'io.dart';
-import 'package.dart';
-import 'source_registry.dart';
-import 'utils.dart';
-
-/// A parsed and validated `pubspec.lock` file.
-class LockFile {
-  /// The packages this lockfile pins.
-  Map<String, PackageId> packages;
-
-  /// Creates a new lockfile containing [ids].
-  factory LockFile(List<PackageId> ids) {
-    var lockFile = new LockFile.empty();
-    for (var id in ids) {
-      if (!id.isRoot) lockFile.packages[id.name] = id;
-    }
-
-    return lockFile;
-  }
-
-  LockFile._(this.packages);
-
-  LockFile.empty()
-      : packages = <String, PackageId>{};
-
-  /// Loads a lockfile from [filePath].
-  factory LockFile.load(String filePath, SourceRegistry sources) {
-    return LockFile._parse(filePath, readTextFile(filePath), sources);
-  }
-
-  /// Parses a lockfile whose text is [contents].
-  factory LockFile.parse(String contents, SourceRegistry sources) {
-    return LockFile._parse(null, contents, sources);
-  }
-
-  /// Parses the lockfile whose text is [contents].
-  ///
-  /// [filePath] is the system-native path to the lockfile on disc. It may be
-  /// `null`.
-  static LockFile _parse(String filePath, String contents,
-      SourceRegistry sources) {
-    var packages = <String, PackageId>{};
-
-    if (contents.trim() == '') return new LockFile.empty();
-
-    var sourceUrl;
-    if (filePath != null) sourceUrl = p.toUri(filePath);
-    var parsed = loadYamlNode(contents, sourceUrl: sourceUrl);
-
-    _validate(parsed is Map, 'The lockfile must be a YAML mapping.', parsed);
-
-    var packageEntries = parsed['packages'];
-    if (packageEntries != null) {
-      _validate(
-          packageEntries is Map,
-          'The "packages" field must be a map.',
-          parsed.nodes['packages']);
-
-      packageEntries.forEach((name, spec) {
-        // Parse the version.
-        _validate(
-            spec.containsKey('version'),
-            'Package $name is missing a version.',
-            spec);
-        var version = new Version.parse(spec['version']);
-
-        // Parse the source.
-        _validate(
-            spec.containsKey('source'),
-            'Package $name is missing a source.',
-            spec);
-        var sourceName = spec['source'];
-
-        _validate(
-            spec.containsKey('description'),
-            'Package $name is missing a description.',
-            spec);
-        var description = spec['description'];
-
-        // Let the source parse the description.
-        var source = sources[sourceName];
-        try {
-          description =
-              source.parseDescription(filePath, description, fromLockFile: true);
-        } on FormatException catch (ex) {
-          throw new SourceSpanFormatException(
-              ex.message,
-              spec.nodes['source'].span);
-        }
-
-        var id = new PackageId(name, sourceName, version, description);
-
-        // Validate the name.
-        _validate(
-            name == id.name,
-            "Package name $name doesn't match ${id.name}.",
-            spec);
-
-        packages[name] = id;
-      });
-    }
-
-    return new LockFile._(packages);
-  }
-
-  /// If [condition] is `false` throws a format error with [message] for [node].
-  static void _validate(bool condition, String message, YamlNode node) {
-    if (condition) return;
-    throw new SourceSpanFormatException(message, node.span);
-  }
-
-  /// Returns the serialized YAML text of the lock file.
-  ///
-  /// [packageDir] is the containing directory of the root package, used to
-  /// properly serialize package descriptions.
-  String serialize(String packageDir, SourceRegistry sources) {
-    // Convert the dependencies to a simple object.
-    var data = {};
-    packages.forEach((name, package) {
-      var description =
-          sources[package.source].serializeDescription(packageDir, package.description);
-
-      data[name] = {
-        'version': package.version.toString(),
-        'source': package.source,
-        'description': description
-      };
-    });
-
-    return """
-# Generated by pub
-# See http://pub.dartlang.org/doc/glossary.html#lockfile
-${yamlToString({'packages': data})}
-""";
-  }
-}