// Copyright 2015 The Chromium Authors. All rights reserved.// Use of this source code is governed by a BSD-style license that can be// found in the LICENSE file.import'dart:async';import'package:logging/logging.dart';import'../artifacts.dart';import'../process.dart';import'flutter_command.dart';finalLogger_logging=newLogger('flutter_tools.upgrade');classUpgradeCommandextendsFlutterCommand{finalStringname='upgrade';finalStringdescription='Upgrade your copy of Flutter.';@overrideFuture<int>runInProject()async{intcode=awaitrunCommandAndStreamOutput(['git','pull','--ff-only'],workingDirectory:ArtifactStore.flutterRoot);if(code!=0)returncode;returnawaitrunCommandAndStreamOutput([sdkBinaryName('pub'),'upgrade']);}}