Move pub into sdk/lib/_internal.

utils/pub/command_update.dart

-// 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 command_update;
-
-import 'dart:async';
-import 'entrypoint.dart';
-import 'log.dart' as log;
-import 'pub.dart';
-
-/// Handles the `update` pub command.
-class UpdateCommand extends PubCommand {
-  String get description =>
-    "Update the current package's dependencies to the latest versions.";
-
-  String get usage => 'pub update [dependencies...]';
-
-  Future onRun() {
-    var future;
-    if (commandOptions.rest.isEmpty) {
-      future = entrypoint.updateAllDependencies();
-    } else {
-      future = entrypoint.updateDependencies(commandOptions.rest);
-    }
-    return future
-        .then((_) => log.message("Dependencies updated!"));
-  }
-}