Add benchmark/test for drawing images across frames (#67176)

dev/benchmarks/macrobenchmarks/lib/src/web/bench_build_image.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:math' as math;
+import 'dart:typed_data';
+
+import 'package:flutter/widgets.dart';
+
+import 'recorder.dart';
+
+const List<int> kTransparentImage = <int>[
+  0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A, 0x00, 0x00, 0x00, 0x0D, 0x49,
+  0x48, 0x44, 0x52, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x08, 0x06,
+  0x00, 0x00, 0x00, 0x1F, 0x15, 0xC4, 0x89, 0x00, 0x00, 0x00, 0x0A, 0x49, 0x44,
+  0x41, 0x54, 0x78, 0x9C, 0x63, 0x00, 0x01, 0x00, 0x00, 0x05, 0x00, 0x01, 0x0D,
+  0x0A, 0x2D, 0xB4, 0x00, 0x00, 0x00, 0x00, 0x49, 0x45, 0x4E, 0x44, 0xAE,
+];
+
+/// An animated GIF image with 3 1x1 pixel frames (a red, green, and blue
+/// frames). The GIF animates forever, and each frame has a 100ms delay.
+const List<int> kAnimatedGif = <int> [
+  0x47, 0x49, 0x46, 0x38, 0x39, 0x61, 0x01, 0x00, 0x01, 0x00, 0xa1, 0x03, 0x00,
+  0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0xff, 0xff, 0xff, 0x21,
+  0xff, 0x0b, 0x4e, 0x45, 0x54, 0x53, 0x43, 0x41, 0x50, 0x45, 0x32, 0x2e, 0x30,
+  0x03, 0x01, 0x00, 0x00, 0x00, 0x21, 0xf9, 0x04, 0x00, 0x0a, 0x00, 0xff, 0x00,
+  0x2c, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x02, 0x02, 0x4c,
+  0x01, 0x00, 0x21, 0xf9, 0x04, 0x00, 0x0a, 0x00, 0xff, 0x00, 0x2c, 0x00, 0x00,
+  0x00, 0x00, 0x01, 0x00, 0x01, 0x00, 0x00, 0x02, 0x02, 0x54, 0x01, 0x00, 0x21,
+  0xf9, 0x04, 0x00, 0x0a, 0x00, 0xff, 0x00, 0x2c, 0x00, 0x00, 0x00, 0x00, 0x01,
+  0x00, 0x01, 0x00, 0x00, 0x02, 0x02, 0x44, 0x01, 0x00, 0x3b,
+];
+
+/// Measures expense of constructing Image widgets.
+class BenchBuildImage extends WidgetRecorder {
+  BenchBuildImage() : super(name: benchmarkName);
+
+  static const String benchmarkName = 'draw_image';
+
+  @override
+  Widget createWidget() {
+    return Directionality(
+      textDirection: TextDirection.ltr,
+      child: _RotatingWidget(
+        child: Row(children: <Widget>[
+          Image.memory(Uint8List.fromList(kTransparentImage)),
+          Image.memory(Uint8List.fromList(kAnimatedGif)),
+        ]),
+      ),
+    );
+  }
+}
+
+class _RotatingWidget extends StatefulWidget {
+  const _RotatingWidget({this.child, Key key}) : super(key: key);
+
+  final Widget child;
+
+  @override
+  _RotatingWidgetState createState() => _RotatingWidgetState();
+}
+
+class _RotatingWidgetState extends State<_RotatingWidget> with SingleTickerProviderStateMixin {
+  AnimationController controller;
+
+  @override
+  void initState() {
+    super.initState();
+    controller = AnimationController(
+      duration: const Duration(milliseconds: 200),
+      vsync: this,
+    )..repeat();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return AnimatedBuilder(
+      animation: controller,
+      builder: (BuildContext context, Widget child) {
+        return Transform(
+          transform: Matrix4.identity()..rotateZ(2 * math.pi * controller.value),
+          child: widget.child,
+        );
+      },
+    );
+  }
+
+}

dev/benchmarks/macrobenchmarks/lib/web_benchmarks.dart

@@ -12,6 +12,7 @@ import 'package:macrobenchmarks/src/web/bench_text_out_of_picture_bounds.dart';
 
 import 'package:gallery/benchmarks/gallery_automator.dart' show DemoType, typeOfDemo;
 
+import 'src/web/bench_build_image.dart';
 import 'src/web/bench_build_material_checkbox.dart';
 import 'src/web/bench_card_infinite_scroll.dart';
 import 'src/web/bench_child_layers.dart';
@@ -39,6 +40,7 @@ const String _galleryBenchmarkPrefix = 'gallery_v2';
 /// When adding a new benchmark, add it to this map. Make sure that the name
 /// of your benchmark is unique.
 final Map<String, RecorderFactory> benchmarks = <String, RecorderFactory>{
+  BenchBuildImage.benchmarkName: () => BenchBuildImage(),
   BenchCardInfiniteScroll.benchmarkName: () => BenchCardInfiniteScroll.forward(),
   BenchCardInfiniteScroll.benchmarkNameBackward: () => BenchCardInfiniteScroll.backward(),
   BenchClippedOutPictures.benchmarkName: () => BenchClippedOutPictures(),