Add Benchmarks and examples to compare swiftui and flutter (#160681)

Partially addresses https://github.com/flutter/flutter/issues/154138,
specifically
[#162025](https://github.com/flutter/flutter/issues/162025),
[#162026](https://github.com/flutter/flutter/issues/162026),
[#162028](https://github.com/flutter/flutter/issues/162028),
[#162029](https://github.com/flutter/flutter/issues/162029)

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [x] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [x] All existing and new tests are passing.

dev/devicelab/bin/tasks/imitation_game_flutter__compile.dart

@@ -0,0 +1,12 @@
+// 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:flutter_devicelab/framework/devices.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/tasks/perf_tests.dart';
+
+Future<void> main() async {
+  deviceOperatingSystem = DeviceOperatingSystem.ios;
+  await task(createImitationGameFlutterTest());
+}

dev/devicelab/bin/tasks/imitation_game_swiftui__compile.dart

@@ -0,0 +1,12 @@
+// 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:flutter_devicelab/framework/devices.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/tasks/perf_tests.dart';
+
+Future<void> main() async {
+  deviceOperatingSystem = DeviceOperatingSystem.ios;
+  await task(createImitationGameSwiftUITest());
+}

dev/devicelab/lib/tasks/perf_tests.dart

@@ -280,6 +280,28 @@ TaskFunction createHelloWorldCompileTest() {
   ).run;
 }
 
+TaskFunction createImitationGameSwiftUITest() {
+  return CompileTest(
+    '${flutterDirectory.path}/dev/benchmarks/imitation_game_swiftui',
+    reportPackageContentSizes: true,
+  ).runSwiftUIApp;
+}
+
+TaskFunction createImitationGameFlutterTest() {
+  flutter(
+    'create',
+    options: <String>[
+      '--platforms=ios',
+      '${flutterDirectory.path}/dev/benchmarks/imitation_game_flutter',
+      '--no-overwrite',
+    ],
+  );
+  return CompileTest(
+    '${flutterDirectory.path}/dev/benchmarks/imitation_game_flutter',
+    reportPackageContentSizes: true,
+  ).run;
+}
+
 TaskFunction createWebCompileTest() {
   return const WebCompileTest().run;
 }
@@ -1687,6 +1709,50 @@ class CompileTest {
     });
   }
 
+  Future<TaskResult> runSwiftUIApp() async {
+    return inDirectory<TaskResult>(testDirectory, () async {
+      await Process.run('xcodebuild', <String>['clean', '-allTargets']);
+
+      int releaseSizeInBytes = 0;
+      final Stopwatch watch = Stopwatch();
+
+      watch.start();
+      await Process.run(workingDirectory: testDirectory, 'xcodebuild', <String>[
+        '-scheme',
+        'hello_world_swiftui',
+        '-target',
+        'hello_world_swiftui',
+        '-sdk',
+        'iphoneos',
+        '-configuration',
+        'Release',
+        '-archivePath',
+        '$testDirectory/hello_world_swiftui',
+        'archive',
+      ]).then((ProcessResult results) {
+        watch.stop();
+        print(results.stdout);
+        if (results.exitCode != 0) {
+          print(results.stderr);
+        }
+      });
+
+      final String appPath =
+          '$testDirectory/hello_world_swiftui.xcarchive/Products/Applications/hello_world_swiftui.app';
+
+      // Zip up the .app file to get an approximation of the .ipa size.
+      await exec('tar', <String>['-zcf', 'app.tar.gz', appPath]);
+      releaseSizeInBytes = await file('$testDirectory/app.tar.gz').length();
+
+      final Map<String, dynamic> metrics = <String, dynamic>{};
+      metrics.addAll(<String, dynamic>{
+        'release_swiftui_compile_millis': watch.elapsedMilliseconds,
+        'release_swiftui_size_bytes': releaseSizeInBytes,
+      });
+      return TaskResult.success(metrics);
+    });
+  }
+
   Future<Map<String, dynamic>> _compileApp({required bool deleteGradleCache}) async {
     await flutter('clean');
     if (deleteGradleCache) {