Add: flutter build ios [--[no-]simulator]

This allows the user to build an iOS application bundle from the command line even if no device is attached to the workstation.

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

@@ -8,12 +8,14 @@ import 'dart:io';
 import '../globals.dart';
 import '../runner/flutter_command.dart';
 import 'build_apk.dart';
+import 'build_ios.dart';
 import 'build_flx.dart';
 
 class BuildCommand extends FlutterCommand {
   BuildCommand() {
     addSubcommand(new BuildApkCommand());
     addSubcommand(new BuildCleanCommand());
+    addSubcommand(new BuildIOSCommand());
     addSubcommand(new BuildFlxCommand());
   }
 

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

+// Copyright 2016 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 '../application_package.dart';
+import '../build_configuration.dart';
+import '../globals.dart';
+import '../ios/mac.dart';
+import '../runner/flutter_command.dart';
+
+class BuildIOSCommand extends FlutterCommand {
+  BuildIOSCommand() {
+    argParser.addFlag('simulator', help: 'Build for the iOS simulator instead of the device');
+  }
+
+  @override
+  final String name = 'ios';
+
+  @override
+  final String description = 'Build an iOS application bundle.';
+
+  @override
+  Future<int> runInProject() async {
+    if (getCurrentHostPlatform() != HostPlatform.mac) {
+      printError('Building for iOS is only supported on the Mac.');
+      return 1;
+    }
+
+    printTrace('Ensuring toolchains are up to date.');
+
+    await Future.wait([
+      downloadToolchain(),
+      downloadApplicationPackages(),
+    ], eagerError: true);
+
+    IOSApp app = applicationPackages.iOS;
+
+    if (app == null) {
+      printError('Application not configured for iOS');
+      return 1;
+    }
+
+    bool forSimulator = argResults['simulator'];
+
+    String logTarget = forSimulator ? "simulator" : "device";
+
+    printStatus('Building the application for $logTarget.');
+
+    bool result = await buildIOSXcodeProject(app, buildForDevice: !forSimulator);
+
+    if (!result) {
+      printError('Encountered error while building for $logTarget.');
+      return 1;
+    }
+
+    printStatus('Done.');
+
+    return 0;
+  }
+}