Add game_template (#1180)

Adds a template / sample for games built in Flutter, with all the bells and whistles, like ads, in-app purchases, audio, main menu, settings, and so on.

Co-authored-by: Parker Lougheed
Co-authored-by: Shams Zakhour

game_template/test/crashlytics_test.dart

@@ -0,0 +1,39 @@
+// Copyright 2022, the Flutter project authors. Please see the AUTHORS file
+// for details. 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:game_template/src/crashlytics/crashlytics.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('filterStackTrace', () {
+    test('keeps current stacktrace intact', () {
+      final original = StackTrace.current;
+      final filtered = filterStackTrace(original).toString().trim();
+
+      expect(filtered, equals(original.toString().trim()));
+    });
+
+    test('parses an empty stacktrace', () {
+      const original = StackTrace.empty;
+      final filtered = filterStackTrace(original).toString().trim();
+
+      expect(filtered, equals(original.toString().trim()));
+    });
+
+    test('removes the head of an example stacktrace', () {
+      final original = StackTrace.fromString(
+          '''       at guardWithCrashlytics.<fn>.<fn>(crashlytics.dart:32)
+       at _BroadcastStreamController.add(_BroadcastStreamController.java)
+       at Logger._publish(logger.dart:276)
+       at Logger.log(logger.dart:200)
+       at Logger.severe(logger.dart:258)
+       at GamesServicesController.initialize(games_services.dart:23)''');
+      final filtered = filterStackTrace(original).toString().trim();
+
+      expect(filtered, isNot(original.toString().trim()));
+      expect(filtered, isNot(contains('at guardWithCrashlytics')));
+      expect(filtered, contains('at GamesServicesController'));
+    });
+  });
+}