[Gallery] Fix directory structure (#312)

gallery/lib/studies/crane/sleep_form.dart

@@ -0,0 +1,45 @@
+// Copyright 2019 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter/material.dart';
+import 'package:gallery/l10n/gallery_localizations.dart';
+
+import 'package:gallery/studies/crane/backlayer.dart';
+import 'package:gallery/studies/crane/header_form.dart';
+
+class SleepForm extends BackLayerItem {
+  SleepForm({int index}) : super(index: index);
+
+  @override
+  _SleepFormState createState() => _SleepFormState();
+}
+
+class _SleepFormState extends State<SleepForm> {
+  final travelerController = TextEditingController();
+  final dateController = TextEditingController();
+  final locationController = TextEditingController();
+
+  @override
+  Widget build(BuildContext context) {
+    return HeaderForm(
+      fields: <HeaderFormField>[
+        HeaderFormField(
+          iconData: Icons.person,
+          title: GalleryLocalizations.of(context).craneFormTravelers,
+          textController: travelerController,
+        ),
+        HeaderFormField(
+          iconData: Icons.date_range,
+          title: GalleryLocalizations.of(context).craneFormDates,
+          textController: dateController,
+        ),
+        HeaderFormField(
+          iconData: Icons.hotel,
+          title: GalleryLocalizations.of(context).craneFormLocation,
+          textController: locationController,
+        ),
+      ],
+    );
+  }
+}