Add a benchmark for simple DisplayLists to exercise the Raster Cache's cache admission algorithm (#97992)

.ci.yaml

@@ -2062,6 +2062,17 @@ targets:
       task_name: picture_cache_perf__timeline_summary
     scheduler: luci
 
+  - name: Linux_android picture_cache_complexity_scoring_perf__timeline_summary
+    recipe: devicelab/devicelab_drone
+    bringup: true
+    presubmit: false
+    timeout: 60
+    properties:
+      tags: >
+        ["devicelab","android","linux"]
+      task_name: picture_cache_complexity_scoring_perf__timeline_summary
+    scheduler: luci
+
   - name: Linux_android platform_channels_benchmarks
     recipe: devicelab/devicelab_drone
     presubmit: false
@@ -3371,6 +3382,17 @@ targets:
       task_name: new_gallery_ios__transition_perf
     scheduler: luci
 
+  - name: Mac_ios picture_cache_complexity_scoring_perf__timeline_summary
+    recipe: devicelab/devicelab_drone
+    bringup: true
+    presubmit: false
+    timeout: 60
+    properties:
+      tags: >
+        ["devicelab","ios","mac"]
+      task_name: picture_cache_complexity_scoring_perf__timeline_summary
+    scheduler: luci
+
   - name: Mac_ios platform_channel_sample_test_ios
     recipe: devicelab/devicelab_drone
     presubmit: false

TESTOWNERS

@@ -113,6 +113,7 @@
 /dev/devicelab/bin/tasks/microbenchmarks.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/new_gallery__transition_perf.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/picture_cache_perf__timeline_summary.dart @zanderso @flutter/engine
+/dev/devicelab/bin/tasks/picture_cache_complexity_scoring_perf__timeline_summary.dart @flar @flutter/engine
 /dev/devicelab/bin/tasks/platform_channel_sample_test.dart @zanderso @flutter/engine
 /dev/devicelab/bin/tasks/platform_interaction_test.dart @stuartmorgan @flutter/plugin
 /dev/devicelab/bin/tasks/platform_view__start_up.dart @zanderso @flutter/engine

dev/benchmarks/macrobenchmarks/lib/common.dart

@@ -8,6 +8,7 @@ const String kBackdropFilterRouteName = '/backdrop_filter';
 const String kPostBackdropFilterRouteName = '/post_backdrop_filter';
 const String kSimpleAnimationRouteName = '/simple_animation';
 const String kPictureCacheRouteName = '/picture_cache';
+const String kPictureCacheComplexityScoringRouteName = '/picture_cache_complexity_scoring';
 const String kLargeImageChangerRouteName = '/large_image_changer';
 const String kLargeImagesRouteName = '/large_images';
 const String kTextRouteName = '/text';

dev/benchmarks/macrobenchmarks/lib/main.dart

@@ -21,6 +21,7 @@ import 'src/large_images.dart';
 import 'src/multi_widget_construction.dart';
 import 'src/opacity_peephole.dart';
 import 'src/picture_cache.dart';
+import 'src/picture_cache_complexity_scoring.dart';
 import 'src/post_backdrop_filter.dart';
 import 'src/simple_animation.dart';
 import 'src/simple_scroll.dart';
@@ -47,6 +48,7 @@ class MacrobenchmarksApp extends StatelessWidget {
         kPostBackdropFilterRouteName: (BuildContext context) => const PostBackdropFilterPage(),
         kSimpleAnimationRouteName: (BuildContext context) => const SimpleAnimationPage(),
         kPictureCacheRouteName: (BuildContext context) => const PictureCachePage(),
+        kPictureCacheComplexityScoringRouteName: (BuildContext context) => const PictureCacheComplexityScoringPage(),
         kLargeImageChangerRouteName: (BuildContext context) => const LargeImageChangerPage(),
         kLargeImagesRouteName: (BuildContext context) => const LargeImagesPage(),
         kTextRouteName: (BuildContext context) => const TextPage(),
@@ -122,6 +124,13 @@ class HomePage extends StatelessWidget {
               Navigator.pushNamed(context, kPictureCacheRouteName);
             },
           ),
+          ElevatedButton(
+            key: const Key(kPictureCacheComplexityScoringRouteName),
+            child: const Text('Picture Cache Complexity Scoring'),
+            onPressed: () {
+              Navigator.pushNamed(context, kPictureCacheComplexityScoringRouteName);
+            },
+          ),
           ElevatedButton(
             key: const Key(kLargeImagesRouteName),
             child: const Text('Large Images'),

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

@@ -0,0 +1,47 @@
+// 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 PictureCacheComplexityScoringPage extends StatelessWidget {
+  const PictureCacheComplexityScoringPage({Key? key}) : super(key: key);
+
+  static const List<String> kTabNames = <String>['1', '2'];
+
+  @override
+  Widget build(BuildContext context) {
+    return DefaultTabController(
+      length: kTabNames.length, // This is the number of tabs.
+      child: Scaffold(
+        appBar: AppBar(
+          title: const Text('Picture Cache Complexity Scoring'),
+          // pinned: true,
+          // expandedHeight: 50.0,
+          // forceElevated: innerBoxIsScrolled,
+          bottom: TabBar(
+            tabs: kTabNames.map((String name) => Tab(text: name)).toList(),
+          ),
+        ),
+        body: TabBarView(
+          key: const Key('tabbar_view_complexity'), // this key is used by the driver test
+          children: kTabNames.map((String name) {
+            return _buildComplexityScoringWidgets(name);
+          }).toList(),
+        ),
+      ),
+    );
+  }
+
+  // For now we just test a single case where the widget being cached is actually
+  // relatively cheap to rasterise, and so should not be in the cache.
+  //
+  // Eventually we can extend this to add new test cases based on the tab name.
+  Widget _buildComplexityScoringWidgets(String name) {
+    return Column(children: <Widget>[
+      Slider(value: 50, label: 'Slider 1', onChanged: (double _) {}, max: 100, divisions: 10,),
+      Slider(value: 50, label: 'Slider 2', onChanged: (double _) {}, max: 100, divisions: 10,),
+      Slider(value: 50, label: 'Slider 3', onChanged: (double _) {}, max: 100, divisions: 10,),
+    ]);
+  }
+}

dev/benchmarks/macrobenchmarks/test_driver/picture_cache_complexity_scoring_perf_test.dart

@@ -0,0 +1,30 @@
+// 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_driver/flutter_driver.dart';
+import 'package:macrobenchmarks/common.dart';
+
+import 'util.dart';
+
+void main() {
+  macroPerfTest(
+    'picture_cache_complexity_scoring_perf',
+    kPictureCacheComplexityScoringRouteName,
+    pageDelay: const Duration(seconds: 1),
+    driverOps: (FlutterDriver driver) async {
+      final SerializableFinder tabBarView = find.byValueKey('tabbar_view_complexity');
+      Future<void> _scrollOnce(double offset) async {
+        // Technically it's not scrolling but moving
+        await driver.scroll(tabBarView, offset, 0.0, const Duration(milliseconds: 300));
+        await Future<void>.delayed(const Duration(milliseconds: 500));
+      }
+      // When we eventually add more test panes we will want to tweak these
+      // to go through all the panes
+      for (int i = 0; i < 6; i += 1) {
+        await _scrollOnce(-300.0);
+        await _scrollOnce(300.0);
+      }
+    },
+  );
+}

dev/devicelab/bin/tasks/picture_cache_complexity_scoring_perf__timeline_summary.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.android;
+  await task(createPictureCacheComplexityScoringPerfTest());
+}

dev/devicelab/lib/tasks/perf_tests.dart

@@ -215,6 +215,15 @@ TaskFunction createPictureCachePerfE2ETest() {
   ).run;
 }
 
+TaskFunction createPictureCacheComplexityScoringPerfTest() {
+  return PerfTest(
+    '${flutterDirectory.path}/dev/benchmarks/macrobenchmarks',
+    'test_driver/run_app.dart',
+    'picture_cache_complexity_scoring_perf',
+    testDriver: 'test_driver/picture_cache_complexity_scoring_perf_test.dart',
+  ).run;
+}
+
 TaskFunction createFlutterGalleryStartupTest({String target = 'lib/main.dart'}) {
   return StartupTest(
     '${flutterDirectory.path}/dev/integration_tests/flutter_gallery',