[web] Make devicePixelRatio ready for multi-view (flutter/engine#44783)

This PR moves the source of truth for`devicePixelRatio` to the `EngineFlutterDisplay` singleton.

Main things that this PR is trying to do:
- `EngineFlutterDisplay` is a singleton that represents information about the display.
  - The `devicePixelRatio` can be overriden in tests.
  - The `browserDevicePixelRatio` gets the value directly from the browser and can't be overriden.
- Remove `EngineSingletonFlutterWindow` and incorporate it into `EngineFlutterWindow`.

engine/src/flutter/ci/licenses_golden/licenses_flutter

@@ -1981,6 +1981,7 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/vertices.dart + ../
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/clipboard.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/color_filter.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/configuration.dart + ../../../flutter/LICENSE
+ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/display.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/dom.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/embedder.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/engine_canvas.dart + ../../../flutter/LICENSE
@@ -4731,6 +4732,7 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/canvaskit/vertices.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/clipboard.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/color_filter.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/configuration.dart
+FILE: ../../../flutter/lib/web_ui/lib/src/engine/display.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/dom.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/embedder.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/engine_canvas.dart

engine/src/flutter/lib/web_ui/lib/src/engine.dart

@@ -54,6 +54,7 @@ export 'engine/canvaskit/vertices.dart';
 export 'engine/clipboard.dart';
 export 'engine/color_filter.dart';
 export 'engine/configuration.dart';
+export 'engine/display.dart';
 export 'engine/dom.dart';
 export 'engine/embedder.dart';
 export 'engine/engine_canvas.dart';

engine/src/flutter/lib/web_ui/lib/src/engine/canvas_pool.dart

@@ -9,6 +9,7 @@ import 'package:meta/meta.dart';
 import 'package:ui/ui.dart' as ui;
 
 import 'browser_detection.dart';
+import 'display.dart';
 import 'dom.dart';
 import 'engine_canvas.dart';
 import 'html/bitmap_canvas.dart';
@@ -20,7 +21,6 @@ import 'html/path/path_utils.dart';
 import 'html/picture.dart';
 import 'html/shaders/image_shader.dart';
 import 'html/shaders/shader.dart';
-import 'platform_dispatcher.dart';
 import 'rrect_renderer.dart';
 import 'safe_browser_api.dart';
 import 'shadow.dart';
@@ -156,9 +156,9 @@ class CanvasPool extends _SaveStackTracking {
       // * To make sure that when we scale the canvas by devicePixelRatio (see
       //   _initializeViewport below) the pixels line up.
       final double cssWidth =
-          _widthInBitmapPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
+          _widthInBitmapPixels / EngineFlutterDisplay.instance.browserDevicePixelRatio;
       final double cssHeight =
-          _heightInBitmapPixels / EnginePlatformDispatcher.browserDevicePixelRatio;
+          _heightInBitmapPixels / EngineFlutterDisplay.instance.browserDevicePixelRatio;
       canvas = _allocCanvas(_widthInBitmapPixels, _heightInBitmapPixels);
       _canvas = canvas;
 
@@ -385,8 +385,7 @@ class CanvasPool extends _SaveStackTracking {
   }
 
   /// Returns effective dpi (browser DPI and pixel density due to transform).
-  double get dpi =>
-      EnginePlatformDispatcher.browserDevicePixelRatio * _density;
+  double get dpi => EngineFlutterDisplay.instance.browserDevicePixelRatio * _density;
 
   void _resetTransform() {
     final DomCanvasElement? canvas = _canvas;

engine/src/flutter/lib/web_ui/lib/src/engine/display.dart

@@ -0,0 +1,61 @@
+// Copyright 2013 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:ui/ui.dart' as ui;
+
+import '../engine.dart';
+
+class EngineFlutterDisplay extends ui.Display {
+  EngineFlutterDisplay({
+    required this.id,
+    required this.size,
+    required this.refreshRate,
+  });
+
+  /// The single [EngineFlutterDisplay] that the web page is rendered on.
+  static EngineFlutterDisplay get instance => _instance;
+  static final EngineFlutterDisplay _instance = EngineFlutterDisplay(
+    id: 0,
+    size: ui.Size(domWindow.screen?.width ?? 0, domWindow.screen?.height ?? 0),
+    refreshRate: 60,
+  );
+
+  @override
+  final int id;
+
+  // TODO(mdebbar): https://github.com/flutter/flutter/issues/133562
+  // `size` and `refreshRate` should be kept up-to-date with the
+  // browser. E.g. the window could be resized or moved to another display with
+  // a different refresh rate.
+
+  @override
+  final ui.Size size;
+
+  @override
+  final double refreshRate;
+
+  @override
+  double get devicePixelRatio =>
+      _debugDevicePixelRatioOverride ?? browserDevicePixelRatio;
+
+  /// The real device pixel ratio of the browser.
+  ///
+  /// This value cannot be overriden by tests, for example.
+  double get browserDevicePixelRatio {
+    final double ratio = domWindow.devicePixelRatio;
+    // Guard against WebOS returning 0.
+    return (ratio == 0.0) ? 1.0 : ratio;
+  }
+
+  /// Overrides the default device pixel ratio.
+  ///
+  /// This is useful in tests to emulate screens of different dimensions.
+  ///
+  /// Passing `null` resets the device pixel ratio to the browser's default.
+  void debugOverrideDevicePixelRatio(double? value) {
+    _debugDevicePixelRatioOverride = value;
+  }
+
+  double? _debugDevicePixelRatioOverride;
+}

engine/src/flutter/lib/web_ui/lib/src/engine/html/bitmap_canvas.dart

@@ -9,11 +9,11 @@ import 'package:ui/ui.dart' as ui;
 
 import '../browser_detection.dart';
 import '../canvas_pool.dart';
+import '../display.dart';
 import '../dom.dart';
 import '../engine_canvas.dart';
 import '../frame_reference.dart';
 import '../html_image_codec.dart';
-import '../platform_dispatcher.dart';
 import '../text/canvas_paragraph.dart';
 import '../util.dart';
 import '../vector_math.dart';
@@ -126,7 +126,7 @@ class BitmapCanvas extends EngineCanvas {
   /// Keeps track of what device pixel ratio was used when this [BitmapCanvas]
   /// was created.
   final double _devicePixelRatio =
-      EnginePlatformDispatcher.browserDevicePixelRatio;
+      EngineFlutterDisplay.instance.browserDevicePixelRatio;
 
   // Compensation for [_initializeViewport] snapping canvas position to 1 pixel.
   int? _canvasPositionX, _canvasPositionY;
@@ -201,14 +201,14 @@ class BitmapCanvas extends EngineCanvas {
 
   static int widthToPhysical(double width) {
     final double boundsWidth = width + 1;
-    return (boundsWidth * EnginePlatformDispatcher.browserDevicePixelRatio)
+    return (boundsWidth * EngineFlutterDisplay.instance.browserDevicePixelRatio)
             .ceil() +
         2 * kPaddingPixels;
   }
 
   static int heightToPhysical(double height) {
     final double boundsHeight = height + 1;
-    return (boundsHeight * EnginePlatformDispatcher.browserDevicePixelRatio)
+    return (boundsHeight * EngineFlutterDisplay.instance.browserDevicePixelRatio)
             .ceil() +
         2 * kPaddingPixels;
   }
@@ -253,8 +253,7 @@ class BitmapCanvas extends EngineCanvas {
   /// * [PersistedPicture._recycleCanvas] which also uses this method
   ///   for the same reason.
   bool isReusable() {
-    return _devicePixelRatio ==
-        EnginePlatformDispatcher.browserDevicePixelRatio;
+    return _devicePixelRatio == EngineFlutterDisplay.instance.browserDevicePixelRatio;
   }
 
   /// Returns a "data://" URI containing a representation of the image in this

engine/src/flutter/lib/web_ui/lib/src/engine/html/surface_stats.dart

@@ -4,8 +4,8 @@
 
 import 'dart:async';
 
+import '../display.dart';
 import '../dom.dart';
-import '../platform_dispatcher.dart';
 import 'bitmap_canvas.dart';
 import 'dom_canvas.dart';
 import 'picture.dart';
@@ -131,9 +131,9 @@ void debugRepaintSurfaceStatsOverlay(PersistedScene scene) {
     ..fill();
 
   final double physicalScreenWidth =
-      domWindow.innerWidth! * EnginePlatformDispatcher.browserDevicePixelRatio;
+      domWindow.innerWidth! * EngineFlutterDisplay.instance.browserDevicePixelRatio;
   final double physicalScreenHeight =
-      domWindow.innerHeight! * EnginePlatformDispatcher.browserDevicePixelRatio;
+      domWindow.innerHeight! * EngineFlutterDisplay.instance.browserDevicePixelRatio;
   final double physicsScreenPixelCount =
       physicalScreenWidth * physicalScreenHeight;
 
@@ -300,9 +300,9 @@ void debugPrintSurfaceStats(PersistedScene scene, int frameNumber) {
       return pixels;
     }).fold(0, (int total, int pixels) => total + pixels);
     final double physicalScreenWidth =
-        domWindow.innerWidth! * EnginePlatformDispatcher.browserDevicePixelRatio;
+        domWindow.innerWidth! * EngineFlutterDisplay.instance.browserDevicePixelRatio;
     final double physicalScreenHeight =
-        domWindow.innerHeight! * EnginePlatformDispatcher.browserDevicePixelRatio;
+        domWindow.innerHeight! * EngineFlutterDisplay.instance.browserDevicePixelRatio;
     final double physicsScreenPixelCount =
         physicalScreenWidth * physicalScreenHeight;
     final double screenPixelRatio = pixelCount / physicsScreenPixelCount;

engine/src/flutter/lib/web_ui/lib/src/engine/platform_dispatcher.dart

@@ -60,24 +60,6 @@ class HighContrastSupport {
   }
 }
 
-class EngineFlutterDisplay extends ui.Display {
-  EngineFlutterDisplay({
-    required this.id,
-    required this.devicePixelRatio,
-    required this.size,
-    required this.refreshRate,
-  });
-
-  @override
-  final int id;
-  @override
-  final double devicePixelRatio;
-  @override
-  final ui.Size size;
-  @override
-  final double refreshRate;
-}
-
 /// Platform event dispatcher.
 ///
 /// This is the central entry point for platform messages and configuration
@@ -141,13 +123,8 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
   }
 
   @override
-  Iterable<ui.Display> get displays => <ui.Display>[
-    EngineFlutterDisplay(
-      id: 0,
-      size: ui.Size(domWindow.screen?.width ?? 0, domWindow.screen?.height ?? 0),
-      devicePixelRatio: domWindow.devicePixelRatio,
-      refreshRate: 60,
-    )
+  Iterable<EngineFlutterDisplay> displays = <EngineFlutterDisplay>[
+    EngineFlutterDisplay.instance,
   ];
 
   /// The current list of windows.
@@ -231,13 +208,6 @@ class EnginePlatformDispatcher extends ui.PlatformDispatcher {
     }
   }
 
-  /// Returns device pixel ratio returned by browser.
-  static double get browserDevicePixelRatio {
-    final double ratio = domWindow.devicePixelRatio;
-    // Guard against WebOS returning 0.
-    return (ratio == 0.0) ? 1.0 : ratio;
-  }
-
   /// A callback invoked when any window begins a frame.
   ///
   /// A callback that is invoked to notify the application that it is an
@@ -1297,7 +1267,7 @@ bool _handleWebTestEnd2EndMessage(MethodCodec codec, ByteData? data) {
   final double ratio = double.parse(decoded.arguments as String);
   switch (decoded.method) {
     case 'setDevicePixelRatio':
-      window.debugOverrideDevicePixelRatio(ratio);
+      EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(ratio);
       EnginePlatformDispatcher.instance.onMetricsChanged!();
       return true;
   }

engine/src/flutter/lib/web_ui/lib/src/engine/safe_browser_api.dart

@@ -20,8 +20,8 @@ import 'dart:typed_data';
 import 'package:ui/ui.dart' as ui;
 
 import 'browser_detection.dart';
+import 'display.dart';
 import 'dom.dart';
-import 'platform_dispatcher.dart';
 import 'vector_math.dart';
 
 export 'package:js/js_util.dart' show allowInterop;
@@ -967,8 +967,8 @@ class OffScreenCanvas {
   static bool? _supported;
 
   void _updateCanvasCssSize(DomCanvasElement element) {
-    final double cssWidth = width / EnginePlatformDispatcher.browserDevicePixelRatio;
-    final double cssHeight = height / EnginePlatformDispatcher.browserDevicePixelRatio;
+    final double cssWidth = width / EngineFlutterDisplay.instance.browserDevicePixelRatio;
+    final double cssHeight = height / EngineFlutterDisplay.instance.browserDevicePixelRatio;
     element.style
       ..position = 'absolute'
       ..width = '${cssWidth}px'

engine/src/flutter/lib/web_ui/lib/src/engine/window.dart

@@ -14,6 +14,7 @@ import 'package:ui/ui.dart' as ui;
 import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 
 import '../engine.dart' show DimensionsProvider, registerHotRestartListener, renderer;
+import 'display.dart';
 import 'dom.dart';
 import 'navigation/history.dart';
 import 'platform_dispatcher.dart';
@@ -31,10 +32,8 @@ const int kImplicitViewId = 0;
 /// The Web implementation of [ui.SingletonFlutterWindow].
 class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   EngineFlutterWindow(this.viewId, this.platformDispatcher) {
-    final EnginePlatformDispatcher engineDispatcher =
-        platformDispatcher as EnginePlatformDispatcher;
-    engineDispatcher.viewData[viewId] = this;
-    engineDispatcher.windowConfigurations[viewId] = const ViewConfiguration();
+    platformDispatcher.viewData[viewId] = this;
+    platformDispatcher.windowConfigurations[viewId] = const ViewConfiguration();
     if (ui_web.isCustomUrlStrategySet) {
       _browserHistory = createHistoryForExistingState(ui_web.urlStrategy);
     }
@@ -46,15 +45,13 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   }
 
   @override
-  ui.Display get display {
-    return ui.PlatformDispatcher.instance.displays.first;
-  }
+  EngineFlutterDisplay get display => EngineFlutterDisplay.instance;
 
   @override
   final int viewId;
 
   @override
-  final ui.PlatformDispatcher platformDispatcher;
+  final EnginePlatformDispatcher platformDispatcher;
 
   /// Handles the browser history integration to allow users to use the back
   /// button, etc.
@@ -203,10 +200,8 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   }
 
   ViewConfiguration get _viewConfiguration {
-    final EnginePlatformDispatcher engineDispatcher =
-        platformDispatcher as EnginePlatformDispatcher;
-    assert(engineDispatcher.windowConfigurations.containsKey(viewId));
-    return engineDispatcher.windowConfigurations[viewId] ??
+    assert(platformDispatcher.windowConfigurations.containsKey(viewId));
+    return platformDispatcher.windowConfigurations[viewId] ??
         const ViewConfiguration();
   }
 
@@ -234,7 +229,21 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   }
 
   @override
-  double get devicePixelRatio => _dimensionsProvider.getDevicePixelRatio();
+  double get devicePixelRatio => display.devicePixelRatio;
+
+  // TODO(mdebbar): Deprecate this and remove it.
+  // https://github.com/flutter/flutter/issues/127395
+  void debugOverrideDevicePixelRatio(double? value) {
+    assert(() {
+      printWarning(
+        'The window.debugOverrideDevicePixelRatio API is deprecated and will '
+        'be removed in a future release. Please use '
+        '`debugOverrideDevicePixelRatio` from `dart:ui_web` instead.',
+      );
+      return true;
+    }());
+    display.debugOverrideDevicePixelRatio(value);
+  }
 
   Stream<ui.Size?> get onResize => _dimensionsProvider.onResize;
 
@@ -352,33 +361,13 @@ class EngineFlutterWindow extends ui.SingletonFlutterWindow {
   ui.Size? debugPhysicalSizeOverride;
 }
 
-/// The Web implementation of [ui.SingletonFlutterWindow].
-class EngineSingletonFlutterWindow extends EngineFlutterWindow {
-  EngineSingletonFlutterWindow(
-      super.windowId, super.platformDispatcher);
-
-  @override
-  double get devicePixelRatio =>
-      _debugDevicePixelRatio ??
-      EnginePlatformDispatcher.browserDevicePixelRatio;
-
-  /// Overrides the default device pixel ratio.
-  ///
-  /// This is useful in tests to emulate screens of different dimensions.
-  void debugOverrideDevicePixelRatio(double? value) {
-    _debugDevicePixelRatio = value;
-  }
-
-  double? _debugDevicePixelRatio;
-}
-
 /// The window singleton.
 ///
 /// `dart:ui` window delegates to this value. However, this value has a wider
 /// API surface, providing Web-specific functionality that the standard
 /// `dart:ui` version does not.
-final EngineSingletonFlutterWindow window =
-    EngineSingletonFlutterWindow(kImplicitViewId, EnginePlatformDispatcher.instance);
+final EngineFlutterWindow window =
+    EngineFlutterWindow(kImplicitViewId, EnginePlatformDispatcher.instance);
 
 /// The Web implementation of [ui.ViewPadding].
 class ViewPadding implements ui.ViewPadding {

engine/src/flutter/lib/web_ui/lib/ui_web/src/ui_web/testing.dart

@@ -13,8 +13,10 @@ extension SingletonFlutterWindowExtension on ui.SingletonFlutterWindow {
 }
 
 /// Overrides the value of [ui.FlutterView.devicePixelRatio] in tests.
+///
+/// Passing `null` resets the device pixel ratio to the browser's default.
 void debugOverrideDevicePixelRatio(double? value) {
-  (ui.window as EngineSingletonFlutterWindow).debugOverrideDevicePixelRatio(value);
+  EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(value);
 }
 
 /// Whether the Flutter engine is running in `flutter test` emulation mode.

engine/src/flutter/lib/web_ui/test/engine/display_test.dart

@@ -0,0 +1,31 @@
+// Copyright 2013 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:test/bootstrap/browser.dart';
+import 'package:test/test.dart';
+import 'package:ui/src/engine.dart';
+import 'package:ui/ui.dart' as ui;
+
+void main() {
+  internalBootstrapBrowserTest(() => testMain);
+}
+
+void testMain() {
+  group('EngineFlutterDisplay', () {
+    test('overrides and restores devicePixelRatio', () {
+      final EngineFlutterDisplay display = EngineFlutterDisplay(
+        id: 0,
+        size: const ui.Size(100.0, 100.0),
+        refreshRate: 60.0,
+      );
+
+      final double originalDevicePixelRatio = display.devicePixelRatio;
+      display.debugOverrideDevicePixelRatio(99.3);
+      expect(display.devicePixelRatio, 99.3);
+
+      display.debugOverrideDevicePixelRatio(null);
+      expect(display.devicePixelRatio, originalDevicePixelRatio);
+    });
+  });
+}

engine/src/flutter/lib/web_ui/test/engine/routing_test.dart

@@ -27,14 +27,14 @@ void main() {
 }
 
 void testMain() {
-  late EngineSingletonFlutterWindow window;
+  late EngineFlutterWindow window;
 
   setUpAll(() async {
     await initializeEngine();
   });
 
   setUp(() {
-    window = EngineSingletonFlutterWindow(0, EnginePlatformDispatcher.instance);
+    window = EngineFlutterWindow(0, EnginePlatformDispatcher.instance);
   });
 
   tearDown(() async {

engine/src/flutter/lib/web_ui/test/engine/surface/platform_view_test.dart

@@ -13,7 +13,7 @@ import 'package:ui/ui_web/src/ui_web.dart' as ui_web;
 import '../../common/matchers.dart';
 
 const MethodCodec codec = StandardMethodCodec();
-final EngineSingletonFlutterWindow window = EngineSingletonFlutterWindow(0, EnginePlatformDispatcher.instance);
+final EngineFlutterWindow window = EngineFlutterWindow(0, EnginePlatformDispatcher.instance);
 
 void main() {
   internalBootstrapBrowserTest(() => testMain);

engine/src/flutter/lib/web_ui/test/engine/surface/scene_builder_test.dart

@@ -38,7 +38,7 @@ void testMain() {
     test('pushTransform implements surface lifecycle', () {
       testLayerLifeCycle((ui.SceneBuilder sceneBuilder, ui.EngineLayer? oldLayer) {
         return sceneBuilder.pushTransform(
-            (Matrix4.identity()..scale(domWindow.devicePixelRatio)).toFloat64());
+            (Matrix4.identity()..scale(EngineFlutterDisplay.instance.browserDevicePixelRatio)).toFloat64());
       }, () {
         return '''<s><flt-transform></flt-transform></s>''';
       });

engine/src/flutter/lib/web_ui/test/engine/surface/surface_test.dart

@@ -161,7 +161,7 @@ void testMain() {
       final SurfaceSceneBuilder builder1 = SurfaceSceneBuilder();
       final PersistedTransform a1 =
           builder1.pushTransform(
-              (Matrix4.identity()..scale(domWindow.devicePixelRatio)).toFloat64()) as PersistedTransform;
+              (Matrix4.identity()..scale(EngineFlutterDisplay.instance.browserDevicePixelRatio)).toFloat64()) as PersistedTransform;
       final PersistedOpacity b1 = builder1.pushOpacity(100) as PersistedOpacity;
       final PersistedTransform c1 =
           builder1.pushTransform(Matrix4.identity().toFloat64()) as PersistedTransform;
@@ -182,7 +182,7 @@ void testMain() {
       final SurfaceSceneBuilder builder2 = SurfaceSceneBuilder();
       final PersistedTransform a2 =
           builder2.pushTransform(
-              (Matrix4.identity()..scale(domWindow.devicePixelRatio)).toFloat64(),
+              (Matrix4.identity()..scale(EngineFlutterDisplay.instance.browserDevicePixelRatio)).toFloat64(),
               oldLayer: a1) as PersistedTransform;
       final PersistedTransform c2 =
           builder2.pushTransform(Matrix4.identity().toFloat64(), oldLayer: c1) as PersistedTransform;

engine/src/flutter/lib/web_ui/test/html/bitmap_canvas_golden_test.dart

@@ -244,8 +244,8 @@ Future<void> testMain() async {
     );
 
     final SceneBuilder sb = SceneBuilder();
-    sb.pushTransform(Matrix4.diagonal3Values(EnginePlatformDispatcher.browserDevicePixelRatio,
-        EnginePlatformDispatcher.browserDevicePixelRatio, 1.0).toFloat64());
+    sb.pushTransform(Matrix4.diagonal3Values(EngineFlutterDisplay.instance.browserDevicePixelRatio,
+        EngineFlutterDisplay.instance.browserDevicePixelRatio, 1.0).toFloat64());
     sb.pushTransform(Matrix4.rotationZ(math.pi / 2).toFloat64());
     sb.pushOffset(0, -500);
     sb.pushClipRect(canvasSize);

engine/src/flutter/lib/web_ui/test/html/compositing/compositing_golden_test.dart

@@ -487,8 +487,8 @@ void _testCullRectComputation() {
     final SurfaceSceneBuilder builder = SurfaceSceneBuilder();
 
     builder.pushTransform(Matrix4.diagonal3Values(
-            EnginePlatformDispatcher.browserDevicePixelRatio,
-            EnginePlatformDispatcher.browserDevicePixelRatio,
+            EngineFlutterDisplay.instance.browserDevicePixelRatio,
+            EngineFlutterDisplay.instance.browserDevicePixelRatio,
             1.0)
         .toFloat64());