Initial layout and theme (#90887)

* Initial layout and theme

* fixed tests

* made page scrollable

* fixes based on Chris on Casey's comments

* removed desktop_window, add errorWidget

* 2nd round of fixes

* fixed linux analyze

* changes based on Casey's comments:

* remove trailing space

* removed obselete macos build code

* add discrepency in project.pbxproj

* addressed Casey's comment

dev/conductor/ui/lib/main.dart

@@ -2,23 +2,33 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'dart:io' as io;
 import 'package:conductor_core/conductor_core.dart';
 import 'package:conductor_core/proto.dart' as pb;
-
 import 'package:file/file.dart';
 import 'package:file/local.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:platform/platform.dart';
 
-const String _title = 'Flutter Conductor';
+import 'widgets/progression.dart';
+
+const String _title = 'Flutter Desktop Conductor (Not ready, do not use)';
 
 const LocalFileSystem _fs = LocalFileSystem();
 const LocalPlatform _platform = LocalPlatform();
 final String _stateFilePath = defaultStateFilePath(_platform);
 
-void main() {
+Future<void> main() async {
+  // The app currently only supports macOS and Linux.
+  if (kIsWeb || io.Platform.isWindows) {
+    throw Exception('The conductor only supports MacOS and Linux desktop');
+  }
   final File _stateFile = _fs.file(_stateFilePath);
-  final pb.ConductorState? state = _stateFile.existsSync() ? readStateFromFile(_stateFile) : null;
+  final pb.ConductorState? state =
+      _stateFile.existsSync() ? readStateFromFile(_stateFile) : null;
+
+  WidgetsFlutterBinding.ensureInitialized();
   runApp(MyApp(state));
 }
 
@@ -34,21 +44,24 @@ class MyApp extends StatelessWidget {
   Widget build(BuildContext context) {
     return MaterialApp(
       title: _title,
-      theme: ThemeData(
-        primarySwatch: Colors.blue,
-      ),
+// TODO(Yugue): Add theming, https://github.com/flutter/flutter/issues/90982.
       home: Scaffold(
         appBar: AppBar(
           title: const Text(_title),
         ),
-        body: Center(
+        body: Padding(
+          padding: const EdgeInsets.all(20.0),
           child: Column(
-            mainAxisAlignment: MainAxisAlignment.center,
+            crossAxisAlignment: CrossAxisAlignment.start,
+            mainAxisAlignment: MainAxisAlignment.start,
             children: <Widget>[
-              Expanded(
-                child: SelectableText(
-                  state != null ? presentState(state!) : 'No persistent state file found at $_stateFilePath',
+              const SelectableText(
+                'Desktop app for managing a release of the Flutter SDK, currently in development',
               ),
+              const SizedBox(height: 20.0),
+              MainProgression(
+                releaseState: state,
+                stateFilePath: _stateFilePath,
               ),
             ],
           ),

dev/conductor/ui/lib/widgets/progression.dart

@@ -0,0 +1,45 @@
+// Copyright 2014 The Flutter 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 'package:conductor_core/conductor_core.dart';
+import 'package:conductor_core/proto.dart' as pb;
+import 'package:flutter/material.dart';
+
+/// Displays the progression and each step of the release from the conductor.
+///
+// TODO(Yugue): Add documentation to explain
+// each step of the release, https://github.com/flutter/flutter/issues/90981.
+class MainProgression extends StatefulWidget {
+  const MainProgression({
+    Key? key,
+    this.releaseState,
+    required this.stateFilePath,
+  }) : super(key: key);
+
+  final pb.ConductorState? releaseState;
+  final String stateFilePath;
+
+  @override
+  MainProgressionState createState() => MainProgressionState();
+}
+
+class MainProgressionState extends State<MainProgression> {
+  @override
+  Widget build(BuildContext context) {
+    return Expanded(
+      child: Scrollbar(
+        isAlwaysShown: true,
+        child: ListView(
+          children: <Widget>[
+            SelectableText(
+              widget.releaseState != null
+                  ? presentState(widget.releaseState!)
+                  : 'No persistent state file found at ${widget.stateFilePath}',
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}

dev/conductor/ui/test/main_test.dart

@@ -10,13 +10,12 @@ import 'package:conductor_ui/main.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
-  group('group', () {
+  group('Main app', () {
     testWidgets('Handles null state', (WidgetTester tester) async {
       await tester.pumpWidget(const MyApp(null));
 
-      expect(find.text('Flutter Conductor'), findsOneWidget);
-      expect(find.textContaining('No persistent state file found at'),
-          findsOneWidget);
+      expect(find.textContaining('Flutter Desktop Conductor'), findsOneWidget);
+      expect(find.textContaining('No persistent state file found at'), findsOneWidget);
     });
 
     testWidgets('App prints release channel from state file',
@@ -27,8 +26,8 @@ void main() {
       );
       await tester.pumpWidget(MyApp(state));
 
-      expect(find.text('Flutter Conductor'), findsOneWidget);
-      expect(find.textContaining(channelName), findsOneWidget);
+      expect(find.textContaining('Flutter Desktop Conductor'), findsOneWidget);
+      expect(find.textContaining('Conductor version'), findsOneWidget);
       expect(find.text('1'), findsNothing);
     });
   }, skip: Platform.isWindows); // This app does not support Windows [intended]