Make clean command top level (#12616)

* Make clean command top level

Fixes https://github.com/flutter/flutter/issues/10783

* remove backwards

packages/flutter_tools/lib/executable.dart

@@ -24,6 +24,7 @@ import 'src/cache.dart';
 import 'src/commands/analyze.dart';
 import 'src/commands/build.dart';
 import 'src/commands/channel.dart';
+import 'src/commands/clean.dart';
 import 'src/commands/config.dart';
 import 'src/commands/create.dart';
 import 'src/commands/daemon.dart';
@@ -68,6 +69,7 @@ Future<Null> main(List<String> args) async {
     new AnalyzeCommand(verboseHelp: verboseHelp),
     new BuildCommand(verboseHelp: verboseHelp),
     new ChannelCommand(),
+    new CleanCommand(),
     new ConfigCommand(verboseHelp: verboseHelp),
     new CreateCommand(),
     new DaemonCommand(hidden: !verboseHelp),

packages/flutter_tools/lib/src/commands/build.dart

@@ -6,10 +6,8 @@ import 'dart:async';
 
 import 'package:meta/meta.dart';
 
-import '../base/common.dart';
 import '../base/file_system.dart';
 import '../base/utils.dart';
-import '../build_info.dart';
 import '../globals.dart';
 import '../runner/flutter_command.dart';
 import 'build_aot.dart';
@@ -21,7 +19,6 @@ class BuildCommand extends FlutterCommand {
   BuildCommand({bool verboseHelp: false}) {
     addSubcommand(new BuildApkCommand());
     addSubcommand(new BuildAotCommand());
-    addSubcommand(new BuildCleanCommand());
     addSubcommand(new BuildIOSCommand());
     addSubcommand(new BuildFlxCommand(verboseHelp: verboseHelp));
   }
@@ -61,30 +58,3 @@ abstract class BuildSubCommand extends FlutterCommand {
     }
   }
 }
-
-class BuildCleanCommand extends FlutterCommand {
-  BuildCleanCommand() {
-    requiresPubspecYaml();
-  }
-
-  @override
-  final String name = 'clean';
-
-  @override
-  final String description = 'Delete the build/ directory.';
-
-  @override
-  Future<Null> runCommand() async {
-    final Directory buildDir = fs.directory(getBuildDirectory());
-    printStatus("Deleting '${buildDir.path}${fs.path.separator}'.");
-
-    if (!buildDir.existsSync())
-      return;
-
-    try {
-      buildDir.deleteSync(recursive: true);
-    } catch (error) {
-      throwToolExit(error.toString());
-    }
-  }
-}

packages/flutter_tools/lib/src/commands/clean.dart

+// Copyright 2017 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 '../base/common.dart';
+import '../base/file_system.dart';
+import '../build_info.dart';
+import '../globals.dart';
+import '../runner/flutter_command.dart';
+
+class CleanCommand extends FlutterCommand {
+  CleanCommand() {
+    requiresPubspecYaml();
+  }
+
+  @override
+  final String name = 'clean';
+
+  @override
+  final String description = 'Delete the build/ directory.';
+
+  @override
+  Future<Null> runCommand() async {
+    final Directory buildDir = fs.directory(getBuildDirectory());
+    printStatus("Deleting '${buildDir.path}${fs.path.separator}'.");
+
+    if (!buildDir.existsSync())
+      return;
+
+    try {
+      buildDir.deleteSync(recursive: true);
+    } catch (error) {
+      throwToolExit(error.toString());
+    }
+  }
+}