Switch date picker to using a custom Dialog

Rather than removing all the padding from an AlertDialog, we now just use
Dialog directly for the date picker.

packages/flutter/lib/material.dart

@@ -28,7 +28,6 @@ export 'src/material/constants.dart';
 export 'src/material/data_table.dart';
 export 'src/material/data_table_source.dart';
 export 'src/material/date_picker.dart';
-export 'src/material/date_picker_dialog.dart';
 export 'src/material/dialog.dart';
 export 'src/material/divider.dart';
 export 'src/material/drawer.dart';

packages/flutter/lib/src/material/date_picker_dialog.dart

-// 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:flutter/widgets.dart';
-
-import 'dialog.dart';
-import 'date_picker.dart';
-import 'flat_button.dart';
-
-class _DatePickerDialog extends StatefulWidget {
-  _DatePickerDialog({
-    Key key,
-    this.initialDate,
-    this.firstDate,
-    this.lastDate
-  }) : super(key: key);
-
-  final DateTime initialDate;
-  final DateTime firstDate;
-  final DateTime lastDate;
-
-  @override
-  _DatePickerDialogState createState() => new _DatePickerDialogState();
-}
-
-class _DatePickerDialogState extends State<_DatePickerDialog> {
-  @override
-  void initState() {
-    super.initState();
-    _selectedDate = config.initialDate;
-  }
-
-  DateTime _selectedDate;
-
-  void _handleDateChanged(DateTime value) {
-    setState(() {
-      _selectedDate = value;
-    });
-  }
-
-  void _handleCancel() {
-    Navigator.pop(context);
-  }
-
-  void _handleOk() {
-    Navigator.pop(context, _selectedDate);
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    // TODO(abarth): Use Dialog directly.
-    return new AlertDialog(
-      content: new DatePicker(
-        selectedDate: _selectedDate,
-        firstDate: config.firstDate,
-        lastDate: config.lastDate,
-        onChanged: _handleDateChanged
-      ),
-      contentPadding: EdgeInsets.zero,
-      actions: <Widget>[
-        new FlatButton(
-          child: new Text('CANCEL'),
-          onPressed: _handleCancel
-        ),
-        new FlatButton(
-          child: new Text('OK'),
-          onPressed: _handleOk
-        ),
-      ]
-    );
-  }
-}
-
-/// Shows a dialog containing a material design date picker.
-///
-/// The returned [Future] resolves to the date selected by the user when the
-/// user closes the dialog. If the user cancels the dialog, the [Future]
-/// resolves to the initialDate.
-///
-/// See also:
-///
-///  * [DatePicker]
-///  * [showTimePicker]
-///  * <https://www.google.com/design/spec/components/pickers.html#pickers-date-pickers>
-Future<DateTime> showDatePicker({
-  BuildContext context,
-  DateTime initialDate,
-  DateTime firstDate,
-  DateTime lastDate
-}) async {
-  DateTime picked = await showDialog(
-    context: context,
-    child: new _DatePickerDialog(
-      initialDate: initialDate,
-      firstDate: firstDate,
-      lastDate: lastDate
-    )
-  );
-  return picked ?? initialDate;
-}

packages/flutter/test/material/date_picker_test.dart

@@ -21,7 +21,7 @@ void main() {
                   child: new Block(
                     children: <Widget>[
                       new Material(
-                        child: new DatePicker(
+                        child: new MonthPicker(
                           firstDate: new DateTime(0),
                           lastDate: new DateTime(9999),
                           key: _datePickerKey,
@@ -43,20 +43,20 @@ void main() {
       )
     );
 
-    await tester.tapAt(const Point(50.0, 200.0));
+    await tester.tapAt(const Point(50.0, 100.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 26)));
     await tester.pump(const Duration(seconds: 2));
 
-    await tester.tapAt(const Point(300.0, 200.0));
+    await tester.tapAt(const Point(300.0, 100.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 1)));
     await tester.pump(const Duration(seconds: 2));
 
-    await tester.tapAt(const Point(380.0, 120.0));
+    await tester.tapAt(const Point(380.0, 20.0));
     await tester.pump();
     await tester.pump(const Duration(seconds: 2));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.JULY, 1)));
 
-    await tester.tapAt(const Point(300.0, 200.0));
+    await tester.tapAt(const Point(300.0, 100.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 5)));
     await tester.pump(const Duration(seconds: 2));
 
@@ -65,7 +65,7 @@ void main() {
     await tester.pump(const Duration(seconds: 2));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 5)));
 
-    await tester.tapAt(const Point(45.0, 370.0));
+    await tester.tapAt(const Point(45.0, 270.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.SEPTEMBER, 25)));
     await tester.pump(const Duration(seconds: 2));
 
@@ -74,7 +74,7 @@ void main() {
     await tester.pump(const Duration(seconds: 2));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.SEPTEMBER, 25)));
 
-    await tester.tapAt(const Point(210.0, 280.0));
+    await tester.tapAt(const Point(210.0, 180.0));
     expect(_selectedDate, equals(new DateTime(2016, DateTime.AUGUST, 17)));
     await tester.pump(const Duration(seconds: 2));
 
@@ -92,10 +92,10 @@ void main() {
                     child: new Material(
                       child: new Block(
                         children: <Widget>[
-                          new DatePicker(
+                          new MonthPicker(
                             firstDate: new DateTime(0),
                             lastDate: new DateTime(9999),
-                            onChanged: null,
+                            onChanged: (DateTime value) { },
                             selectedDate: new DateTime(2000, DateTime.JANUARY, 1)
                           )
                         ]

packages/flutter/test/widget/date_picker_test_disabled.dart

@@ -12,7 +12,7 @@ void main() {
     Widget widget = new Material(
       child: new Block(
         children: <Widget>[
-          new DatePicker(
+          new MonthPicker(
             selectedDate: new DateTime.utc(2015, 6, 9, 7, 12),
             firstDate: new DateTime.utc(2013),
             lastDate: new DateTime.utc(2018),