adding packages

deprecated/flutter_cli/lib/src/file_writer.dart

@@ -0,0 +1,32 @@
+// Copyright 2017 Google Inc.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file or at
+// https://developers.google.com/open-source/licenses/bsd
+
+import 'dart:io';
+
+import 'app_logger.dart';
+
+class FileWriter {
+  static FileWriter writer = new FileWriter._();
+
+  FileWriter._();
+
+  /// Writes content to [destination]. Throws StateError if
+  /// destination exists. Folder will be created if not exists.
+  void write(String destination, String content) {
+    var file = new File(destination);
+
+    if (file.existsSync()) {
+      throw new StateError('File $destination already exists');
+    }
+
+    if (!file.parent.existsSync()) {
+      file.parent.createSync(recursive: true);
+    }
+
+    AppLogger.log.info('Saving $destination');
+    file.writeAsStringSync(content);
+  }
+}