[Gallery] Fix directory structure (#312)

gallery/lib/main.dart

@@ -0,0 +1,81 @@
+// 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 'dart:io';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter/scheduler.dart' show timeDilation;
+import 'package:flutter_localized_locales/flutter_localized_locales.dart';
+import 'package:google_fonts/google_fonts.dart';
+import 'package:gallery/constants.dart';
+import 'package:gallery/data/gallery_options.dart';
+import 'package:gallery/l10n/gallery_localizations.dart';
+import 'package:gallery/pages/backdrop.dart';
+import 'package:gallery/pages/splash.dart';
+import 'package:gallery/themes/gallery_theme_data.dart';
+
+void setOverrideForDesktop() {
+  if (kIsWeb) return;
+
+  if (Platform.isMacOS) {
+    debugDefaultTargetPlatformOverride = TargetPlatform.iOS;
+  } else if (Platform.isLinux || Platform.isWindows) {
+    debugDefaultTargetPlatformOverride = TargetPlatform.android;
+  } else if (Platform.isFuchsia) {
+    debugDefaultTargetPlatformOverride = TargetPlatform.fuchsia;
+  }
+}
+
+void main() {
+  setOverrideForDesktop();
+  GoogleFonts.config.allowHttp = false;
+  runApp(GalleryApp());
+}
+
+class GalleryApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return ModelBinding(
+      initialModel: GalleryOptions(
+        themeMode: ThemeMode.system,
+        textScaleFactor: systemTextScaleFactorOption,
+        customTextDirection: CustomTextDirection.localeBased,
+        locale: null,
+        timeDilation: timeDilation,
+        platform: defaultTargetPlatform,
+      ),
+      child: Builder(
+        builder: (context) {
+          return MaterialApp(
+            title: 'Gallery',
+            debugShowCheckedModeBanner: false,
+            themeMode: GalleryOptions.of(context).themeMode,
+            theme: GalleryThemeData.lightThemeData.copyWith(
+              platform: GalleryOptions.of(context).platform,
+            ),
+            darkTheme: GalleryThemeData.darkThemeData.copyWith(
+              platform: GalleryOptions.of(context).platform,
+            ),
+            localizationsDelegates: [
+              ...GalleryLocalizations.localizationsDelegates,
+              LocaleNamesLocalizationsDelegate()
+            ],
+            supportedLocales: GalleryLocalizations.supportedLocales,
+            locale: GalleryOptions.of(context).locale,
+            localeResolutionCallback: (locale, supportedLocales) {
+              deviceLocale = locale;
+              return locale;
+            },
+            home: ApplyTextOptions(
+              child: SplashPage(
+                child: AnimatedBackdrop(),
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+}