Add a test to exercise multiple async microtasks in frame workload (#79163)

dev/benchmarks/macrobenchmarks/lib/common.dart

@@ -20,6 +20,7 @@ const String kMultiWidgetConstructionRouteName = '/multi_widget_construction';
 const String kHeavyGridViewRouteName = '/heavy_gridview';
 const String kSimpleScrollRouteName = '/simple_scroll';
 const String kStackSizeRouteName = '/stack_size';
+const String kAnimationWithMicrotasksRouteName = '/animation_with_microtasks';
 
 const String kScrollableName = '/macrobenchmark_listview';
 

dev/benchmarks/macrobenchmarks/lib/main.dart

@@ -7,6 +7,7 @@ import 'package:flutter/material.dart';
 import 'common.dart';
 
 import 'src/animated_placeholder.dart';
+import 'src/animation_with_microtasks.dart';
 import 'src/backdrop_filter.dart';
 import 'src/color_filter_and_fade.dart';
 import 'src/cubic_bezier.dart';
@@ -56,6 +57,7 @@ class MacrobenchmarksApp extends StatelessWidget {
         kHeavyGridViewRouteName: (BuildContext context) => const HeavyGridViewPage(),
         kSimpleScrollRouteName: (BuildContext context) => const SimpleScroll(),
         kStackSizeRouteName: (BuildContext context) => const StackSizePage(),
+        kAnimationWithMicrotasksRouteName: (BuildContext context) => const AnimationWithMicrotasks(),
       },
     );
   }
@@ -192,6 +194,13 @@ class HomePage extends StatelessWidget {
               Navigator.pushNamed(context, kStackSizeRouteName);
             },
           ),
+          ElevatedButton(
+            key: const Key(kAnimationWithMicrotasksRouteName),
+            child: const Text('Animation With Microtasks'),
+            onPressed: () {
+              Navigator.pushNamed(context, kAnimationWithMicrotasksRouteName);
+            },
+          ),
         ],
       ),
     );

dev/benchmarks/macrobenchmarks/lib/src/animation_with_microtasks.dart

+// 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/material.dart';
+
+class AnimationWithMicrotasks extends StatefulWidget {
+  const AnimationWithMicrotasks({Key key}) : super(key: key);
+
+  @override
+  _AnimationWithMicrotasksState createState() =>
+      _AnimationWithMicrotasksState();
+}
+
+class _AnimationWithMicrotasksState extends State<AnimationWithMicrotasks> {
+  final _ChunkedWork work = _ChunkedWork();
+
+  @override
+  void initState() {
+    super.initState();
+    work.start();
+  }
+
+  @override
+  void dispose() {
+    work.cancel();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return const Scaffold(
+      backgroundColor: Colors.grey,
+      body: Center(
+        child: SizedBox(
+          width: 200,
+          height: 100,
+          child: LinearProgressIndicator(),
+        ),
+      ),
+    );
+  }
+}
+
+class _ChunkedWork {
+  bool _canceled = false;
+
+  Future<void> start() async {
+    // Run 100 pieces of synchronous work.
+    // Chunked up to allow frames to be drawn.
+    for (int i = 0; i < 100; ++i) {
+      _chunkedSynchronousWork();
+    }
+  }
+
+  void cancel() {
+    _canceled = true;
+  }
+
+  Future<void> _chunkedSynchronousWork() async {
+    while (!_canceled) {
+      // Yield to the event loop to let engine draw frames.
+      await Future<void>.delayed(Duration.zero);
+
+      // Perform synchronous computation for 1 ms.
+      _syncComputationFor(const Duration(milliseconds: 1));
+    }
+  }
+
+  void _syncComputationFor(Duration duration) {
+    final Stopwatch sw = Stopwatch()..start();
+    while (!_canceled && sw.elapsed < duration) {}
+  }
+}

dev/benchmarks/macrobenchmarks/test_driver/animation_with_microtasks_perf_test.dart

+// 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:macrobenchmarks/common.dart';
+
+import 'util.dart';
+
+void main() {
+  macroPerfTest(
+    'animation_with_microtasks_perf',
+    kAnimationWithMicrotasksRouteName,
+    pageDelay: const Duration(seconds: 1),
+    duration: const Duration(seconds: 10),
+  );
+}

dev/devicelab/bin/tasks/animation_with_microtasks_perf_ios__timeline_summary.dart

+// 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/tasks/perf_tests.dart';
+import 'package:flutter_devicelab/framework/adb.dart';
+import 'package:flutter_devicelab/framework/framework.dart';
+
+Future<void> main() async {
+  deviceOperatingSystem = DeviceOperatingSystem.ios;
+  await task(createAnimationWithMicrotasksPerfTest());
+}

dev/devicelab/lib/tasks/perf_tests.dart

@@ -151,6 +151,17 @@ TaskFunction createBackdropFilterPerfTest({bool measureCpuGpu = true}) {
   ).run;
 }
 
+TaskFunction createAnimationWithMicrotasksPerfTest({bool measureCpuGpu = true}) {
+  return PerfTest(
+    '${flutterDirectory.path}/dev/benchmarks/macrobenchmarks',
+    'test_driver/run_app.dart',
+    'animation_with_microtasks_perf',
+    measureCpuGpu: measureCpuGpu,
+    testDriver: 'test_driver/animation_with_microtasks_perf_test.dart',
+    saveTraceFile: true,
+  ).run;
+}
+
 TaskFunction createBackdropFilterPerfE2ETest() {
   return PerfTest.e2e(
     '${flutterDirectory.path}/dev/benchmarks/macrobenchmarks',

dev/prod_builders.json

@@ -942,6 +942,12 @@
       "task_name": "mac_tool_integration_tests_3_3",
       "flaky": false
     },
+    {
+      "name": "Mac_ios animation_with_microtasks_perf_ios__timeline_summary",
+      "repo": "flutter",
+      "task_name": "mac_ios_animation_with_microtasks_perf_ios__timeline_summary",
+      "flaky": false
+    },
     {
       "name": "Mac_ios backdrop_filter_perf_ios__timeline_summary",
       "repo": "flutter",