A benchmark test case for measuring scroll smoothness (#61998)

dev/benchmarks/complex_layout/android/settings.gradle

@@ -3,3 +3,13 @@
 // found in the LICENSE file.
 
 include ':app'
+
+def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
+def properties = new Properties()
+
+assert localPropertiesFile.exists()
+localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
+
+def flutterSdkPath = properties.getProperty("flutter.sdk")
+assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"

dev/benchmarks/complex_layout/lib/main.dart

@@ -109,6 +109,7 @@ class ComplexLayoutState extends State<ComplexLayout> {
           Expanded(
             child: ListView.builder(
               key: const Key('complex-scroll'), // this key is used by the driver test
+              controller: ScrollController(),  // So that the scroll offset can be tracked
               itemBuilder: (BuildContext context, int index) {
                 if (index % 2 == 0)
                   return FancyImageItem(index, key: PageStorageKey<int>(index));

dev/benchmarks/complex_layout/pubspec.yaml

@@ -3,7 +3,7 @@ description: A benchmark of a relatively complex layout.
 
 environment:
   # The pub client defaults to an <2.0.0 sdk constraint which we need to explicitly overwrite.
-  sdk: ">=2.0.0-dev.68.0 <3.0.0"
+  sdk: ">=2.2.2 <3.0.0"
 
 dependencies:
   flutter:
@@ -46,6 +46,7 @@ dev_dependencies:
   flutter_test:
     sdk: flutter
   test: 1.16.0-nullsafety.1
+  e2e: 0.7.0
 
   _fe_analyzer_shared: 7.0.0 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
   analyzer: 0.39.17 # THIS LINE IS AUTOGENERATED - TO UPDATE USE "flutter update-packages --force-upgrade"
@@ -90,4 +91,4 @@ flutter:
     - packages/flutter_gallery_assets/people/square/ali.png
     - packages/flutter_gallery_assets/places/india_chettinad_silk_maker.png
 
-# PUBSPEC CHECKSUM: 6832
+# PUBSPEC CHECKSUM: 047d

dev/benchmarks/complex_layout/test_driver/measure_scroll_smoothness_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 'dart:async';
+
+import 'package:e2e/e2e_driver.dart' as driver;
+
+Future<void> main() => driver.e2eDriver(
+  timeout: const Duration(minutes: 5),
+  responseDataCallback: (Map<String, dynamic> data) async {
+    await driver.writeResponseData(
+      data,
+      testOutputFilename: 'scroll_smoothness_test',
+    );
+  }
+);

dev/devicelab/bin/tasks/complex_layout_android__scroll_smoothness.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 'dart:async';
+
+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.android;
+  await task(createsScrollSmoothnessPerfTest());
+}

dev/devicelab/lib/tasks/perf_tests.dart

@@ -298,6 +298,54 @@ TaskFunction createsMultiWidgetConstructPerfE2ETest() {
   ).run;
 }
 
+TaskFunction createsScrollSmoothnessPerfTest() {
+  final String testDirectory =
+      '${flutterDirectory.path}/dev/benchmarks/complex_layout';
+  const String testTarget = 'test/measure_scroll_smoothness.dart';
+  return () {
+    return inDirectory<TaskResult>(testDirectory, () async {
+      final Device device = await devices.workingDevice;
+      await device.unlock();
+      final String deviceId = device.deviceId;
+      await flutter('packages', options: <String>['get']);
+
+      await flutter('drive', options: <String>[
+        '-v',
+        '--verbose-system-logs',
+        '--profile',
+        '-t', testTarget,
+        '-d',
+        deviceId,
+      ]);
+      final Map<String, dynamic> data = json.decode(
+        file('$testDirectory/build/scroll_smoothness_test.json').readAsStringSync(),
+      ) as Map<String, dynamic>;
+
+      final Map<String, dynamic> result = <String, dynamic>{};
+      void addResult(dynamic data, String suffix) {
+        assert(data is Map<String, dynamic>);
+        const List<String> metricKeys = <String>[
+          'janky_count',
+          'average_abs_jerk',
+          'dropped_frame_count',
+        ];
+        for (final String key in metricKeys) {
+          result[key+suffix] = data[key];
+        }
+      }
+      addResult(data['resample on with 90Hz input'], '_with_resampler_90Hz');
+      addResult(data['resample on with 59Hz input'], '_with_resampler_59Hz');
+      addResult(data['resample off with 90Hz input'], '_without_resampler_90Hz');
+      addResult(data['resample off with 59Hz input'], '_without_resampler_59Hz');
+
+      return TaskResult.success(
+        result,
+        benchmarkScoreKeys: result.keys.toList(),
+      );
+    });
+  };
+}
+
 TaskFunction createFramePolicyIntegrationTest() {
   final String testDirectory =
       '${flutterDirectory.path}/dev/benchmarks/macrobenchmarks';

dev/devicelab/manifest.yaml

@@ -114,6 +114,14 @@ tasks:
 
   # Android on-device tests
 
+  complex_layout_android__scroll_smoothness:
+    description: >
+      Measures the smoothness of scrolling of the Complex Layout sample app on
+      Android.
+    stage: devicelab
+    required_agent_capabilities: ["linux/android"]
+    flaky: true
+
   complex_layout_scroll_perf__timeline_summary:
     description: >
       Measures the runtime performance of the Complex Layout sample app on

packages/flutter_test/lib/src/binding.dart

@@ -1504,7 +1504,6 @@ class LiveTestWidgetsFlutterBinding extends TestWidgetsFlutterBinding {
             renderView._pointers[event.pointer].decay = _kPointerDecay;
           _handleViewNeedsPaint();
         } else if (event.down) {
-          assert(event is PointerDownEvent);
           renderView._pointers[event.pointer] = _LiveTestPointerRecord(
             event.pointer,
             event.position,