Regenerate pub sources.

sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart

Index: sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart
diff --git a/sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart b/sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart
index 3bcfbacdc725961d8c77eddf1174c707731b8666..a3049cb5e05783191f8419ae5f7cf10262ce70f1 100644
--- a/sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart
+++ b/sdk/lib/_internal/pub_generated/lib/src/source/unknown.dart
@@ -1,23 +1,47 @@
+// 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.source.unknown;
+
 import 'dart:async';
+
 import '../package.dart';
 import '../pubspec.dart';
 import '../source.dart';
+
+/// A [Null Object] that represents a source not recognized by pub.
+///
+/// It provides some default behavior so that pub can work with sources it
+/// doesn't recognize.
+///
+/// [null object]: http://en.wikipedia.org/wiki/Null_Object_pattern
 class UnknownSource extends Source {
   final String name;
+
   UnknownSource(this.name);
+
+  /// Two unknown sources are the same if their names are the same.
   bool operator ==(other) => other is UnknownSource && other.name == name;
+
   int get hashCode => name.hashCode;
+
   Future<Pubspec> doDescribe(PackageId id) =>
       throw new UnsupportedError(
           "Cannot describe a package from unknown source '$name'.");
+
   Future get(PackageId id, String symlink) =>
       throw new UnsupportedError("Cannot get an unknown source '$name'.");
+
+  /// Returns the directory where this package can be found locally.
   Future<String> getDirectory(PackageId id) =>
       throw new UnsupportedError(
           "Cannot find a package from an unknown source '$name'.");
+
   bool descriptionsEqual(description1, description2) =>
       description1 == description2;
+
+  /// Unknown sources do no validation.
   dynamic parseDescription(String containingPath, description,
       {bool fromLockFile: false}) =>
       description;