Reverts "[web] Fix Scene clip bounds. Trigger resize on DPR Change." (flutter#50404)

Reverts flutter#50161

Initiated by: jonahwilliams

Reason for reverting: This is causing what looks like bogus goldens on the framework -> engine roll: flutter/flutter#142966

Original PR Author: ditman

Reviewed By: {yjbanov, mdebbar}

This change reverts the following previous change:
Original Description:
The Scene of the HTML renderer is passing incorrect size information to the engine, and when DPR<1, it can result in elements being culled off of the viewport.

In addition to that, when an app is embedded, not all changes in DPR cause a Resize event (only those some of the dimensions fails by a rounding error!), so this PR ensures that all DPR events in embedded trigger a resize event.

### Issues

Fixes flutter/flutter#129182

### Testing

Looking good at: https://dit-astral-test.web.app

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

Author: auto-submit[bot]

ci/licenses_golden/licenses_flutter

@@ -6134,7 +6134,6 @@ ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/vector_math.dart + ../../../f
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/custom_element_dimensions_provider.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/dimensions_provider.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/full_page_dimensions_provider.dart + ../../../flutter/LICENSE
-ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/display_dpr_stream.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dom_manager.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/embedding_strategy/custom_element_embedding_strategy.dart + ../../../flutter/LICENSE
 ORIGIN: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/embedding_strategy/embedding_strategy.dart + ../../../flutter/LICENSE
@@ -8998,7 +8997,6 @@ FILE: ../../../flutter/lib/web_ui/lib/src/engine/vector_math.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/custom_element_dimensions_provider.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/dimensions_provider.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/full_page_dimensions_provider.dart
-FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/display_dpr_stream.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/dom_manager.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/embedding_strategy/custom_element_embedding_strategy.dart
 FILE: ../../../flutter/lib/web_ui/lib/src/engine/view_embedder/embedding_strategy/embedding_strategy.dart

lib/web_ui/lib/src/engine.dart

@@ -190,7 +190,6 @@ export 'engine/vector_math.dart';
 export 'engine/view_embedder/dimensions_provider/custom_element_dimensions_provider.dart';
 export 'engine/view_embedder/dimensions_provider/dimensions_provider.dart';
 export 'engine/view_embedder/dimensions_provider/full_page_dimensions_provider.dart';
-export 'engine/view_embedder/display_dpr_stream.dart';
 export 'engine/view_embedder/dom_manager.dart';
 export 'engine/view_embedder/embedding_strategy/custom_element_embedding_strategy.dart';
 export 'engine/view_embedder/embedding_strategy/embedding_strategy.dart';

lib/web_ui/lib/src/engine/html/scene.dart

@@ -45,15 +45,9 @@ class PersistedScene extends PersistedContainerSurface {
 
   @override
   void recomputeTransformAndClip() {
-    // The scene clip is the size of the entire window **in Logical pixels**.
-    //
-    // Even though the majority of the engine uses `physicalSize`, there are some
-    // bits (like the HTML renderer, or dynamic view sizing) that are implemented
-    // using CSS, and CSS operates in logical pixels.
-    //
-    // See also: [EngineFlutterView.resize].
-    final ui.Size bounds = window.physicalSize / window.devicePixelRatio;
-    localClipBounds = ui.Rect.fromLTRB(0, 0, bounds.width, bounds.height);
+    // The scene clip is the size of the entire window.
+    final ui.Size screen = window.physicalSize;
+    localClipBounds = ui.Rect.fromLTRB(0, 0, screen.width, screen.height);
     projectedClip = null;
   }
 

lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/custom_element_dimensions_provider.dart

@@ -4,7 +4,6 @@
 
 import 'dart:async';
 
-import 'package:ui/src/engine/display.dart';
 import 'package:ui/src/engine/dom.dart';
 import 'package:ui/src/engine/window.dart';
 import 'package:ui/ui.dart' as ui show Size;
@@ -13,36 +12,21 @@ import 'dimensions_provider.dart';
 
 /// This class provides observable, real-time dimensions of a host element.
 ///
-/// This class needs a `Stream` of `devicePixelRatio` changes, like the one
-/// provided by [DisplayDprStream], because html resize observers do not report
-/// DPR changes.
-///
 /// All the measurements returned from this class are potentially *expensive*,
 /// and should be cached as needed. Every call to every method on this class
 /// WILL perform actual DOM measurements.
-///
-/// This broadcasts `null` size events, to match the implementation of the
-/// FullPageDimensionsProvider, but it could broadcast the size coming from the
-/// DomResizeObserverEntry. Further changes in the engine are required for this
-/// to be effective.
 class CustomElementDimensionsProvider extends DimensionsProvider {
   /// Creates a [CustomElementDimensionsProvider] from a [_hostElement].
-  CustomElementDimensionsProvider(this._hostElement, {
-    Stream<double>? onDprChange,
-  }) {
-    // Send a resize event when the page DPR changes.
-    _dprChangeStreamSubscription = onDprChange?.listen((_) {
-      _broadcastSize(null);
-    });
-
+  CustomElementDimensionsProvider(this._hostElement) {
     // Hook up a resize observer on the hostElement (if supported!).
     _hostElementResizeObserver = createDomResizeObserver((
       List<DomResizeObserverEntry> entries,
       DomResizeObserver _,
     ) {
-      for (final DomResizeObserverEntry _ in entries) {
-        _broadcastSize(null);
-      }
+      entries
+          .map((DomResizeObserverEntry entry) =>
+              ui.Size(entry.contentRect.width, entry.contentRect.height))
+          .forEach(_broadcastSize);
     });
 
     assert(() {
@@ -61,12 +45,11 @@ class CustomElementDimensionsProvider extends DimensionsProvider {
 
   // Handle resize events
   late DomResizeObserver? _hostElementResizeObserver;
-  late StreamSubscription<double>? _dprChangeStreamSubscription;
-  final StreamController<ui.Size?> _onResizeStreamController =
-      StreamController<ui.Size?>.broadcast();
+  final StreamController<ui.Size> _onResizeStreamController =
+      StreamController<ui.Size>.broadcast();
 
   // Broadcasts the last seen `Size`.
-  void _broadcastSize(ui.Size? size) {
+  void _broadcastSize(ui.Size size) {
     _onResizeStreamController.add(size);
   }
 
@@ -75,17 +58,16 @@ class CustomElementDimensionsProvider extends DimensionsProvider {
     super.close();
     _hostElementResizeObserver?.disconnect();
     // ignore:unawaited_futures
-    _dprChangeStreamSubscription?.cancel();
-    // ignore:unawaited_futures
     _onResizeStreamController.close();
   }
 
   @override
-  Stream<ui.Size?> get onResize => _onResizeStreamController.stream;
+  Stream<ui.Size> get onResize => _onResizeStreamController.stream;
 
   @override
   ui.Size computePhysicalSize() {
-    final double devicePixelRatio = EngineFlutterDisplay.instance.devicePixelRatio;
+    final double devicePixelRatio = getDevicePixelRatio();
+
     return ui.Size(
       _hostElement.clientWidth * devicePixelRatio,
       _hostElement.clientHeight * devicePixelRatio,

lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/dimensions_provider.dart

@@ -5,11 +5,11 @@
 import 'dart:async';
 
 import 'package:meta/meta.dart';
-import 'package:ui/src/engine/dom.dart';
-import 'package:ui/src/engine/view_embedder/display_dpr_stream.dart';
 import 'package:ui/src/engine/window.dart';
 import 'package:ui/ui.dart' as ui show Size;
 
+import '../../display.dart';
+import '../../dom.dart';
 import 'custom_element_dimensions_provider.dart';
 import 'full_page_dimensions_provider.dart';
 
@@ -32,15 +32,18 @@ abstract class DimensionsProvider {
   /// Creates the appropriate DimensionsProvider depending on the incoming [hostElement].
   factory DimensionsProvider.create({DomElement? hostElement}) {
     if (hostElement != null) {
-      return CustomElementDimensionsProvider(
-        hostElement,
-        onDprChange: DisplayDprStream.instance.dprChanged,
-      );
+      return CustomElementDimensionsProvider(hostElement);
     } else {
       return FullPageDimensionsProvider();
     }
   }
 
+  /// Returns the DPI reported by the browser.
+  double getDevicePixelRatio() {
+    // This is overridable in tests.
+    return EngineFlutterDisplay.instance.devicePixelRatio;
+  }
+
   /// Returns the [ui.Size] of the "viewport".
   ///
   /// This function is expensive. It triggers browser layout if there are
@@ -54,16 +57,6 @@ abstract class DimensionsProvider {
   );
 
   /// Returns a Stream with the changes to [ui.Size] (when cheap to get).
-  ///
-  /// Currently this Stream always returns `null` measurements because the
-  /// resize event that we use for [FullPageDimensionsProvider] does not contain
-  /// the new size, so users of this Stream everywhere immediately retrieve the
-  /// new `physicalSize` from the window.
-  ///
-  /// The [CustomElementDimensionsProvider] *could* broadcast the new size, but
-  /// to keep both implementations consistent (and their consumers), for now all
-  /// events from this Stream are going to be `null` (until we find a performant
-  /// way to retrieve the dimensions in full-page mode).
   Stream<ui.Size?> get onResize;
 
   /// Whether the [DimensionsProvider] instance has been closed or not.

lib/web_ui/lib/src/engine/view_embedder/dimensions_provider/full_page_dimensions_provider.dart

@@ -5,7 +5,6 @@
 import 'dart:async';
 
 import 'package:ui/src/engine/browser_detection.dart';
-import 'package:ui/src/engine/display.dart';
 import 'package:ui/src/engine/dom.dart';
 import 'package:ui/src/engine/window.dart';
 import 'package:ui/ui.dart' as ui show Size;
@@ -68,7 +67,7 @@ class FullPageDimensionsProvider extends DimensionsProvider {
     late double windowInnerWidth;
     late double windowInnerHeight;
     final DomVisualViewport? viewport = domWindow.visualViewport;
-    final double devicePixelRatio = EngineFlutterDisplay.instance.devicePixelRatio;
+    final double devicePixelRatio = getDevicePixelRatio();
 
     if (viewport != null) {
       if (operatingSystem == OperatingSystem.iOs) {
@@ -103,7 +102,7 @@ class FullPageDimensionsProvider extends DimensionsProvider {
     double physicalHeight,
     bool isEditingOnMobile,
   ) {
-    final double devicePixelRatio = EngineFlutterDisplay.instance.devicePixelRatio;
+    final double devicePixelRatio = getDevicePixelRatio();
     final DomVisualViewport? viewport = domWindow.visualViewport;
     late double windowInnerHeight;
 

lib/web_ui/lib/src/engine/view_embedder/display_dpr_stream.dart

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+@TestOn('browser')
+library;
+
 import 'dart:async';
 
 import 'package:test/bootstrap/browser.dart';
@@ -106,48 +109,23 @@ void doTests() {
     });
 
     test('funnels resize events on sizeSource', () async {
-      EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(2.7);
-
       sizeSource
         ..style.width = '100px'
         ..style.height = '100px';
 
-      expect(provider.onResize.first, completes);
-      expect(provider.computePhysicalSize(), const ui.Size(270, 270));
+      expect(await provider.onResize.first, const ui.Size(100, 100));
 
       sizeSource
         ..style.width = '200px'
         ..style.height = '200px';
 
-      expect(provider.onResize.first, completes);
-      expect(provider.computePhysicalSize(), const ui.Size(540, 540));
+      expect(await provider.onResize.first, const ui.Size(200, 200));
 
       sizeSource
         ..style.width = '300px'
         ..style.height = '300px';
 
-      expect(provider.onResize.first, completes);
-      expect(provider.computePhysicalSize(), const ui.Size(810, 810));
-    });
-
-    test('funnels DPR change events too', () async {
-      // Override the source of DPR events...
-      final StreamController<double> dprController =
-          StreamController<double>.broadcast();
-
-      // Inject the dprController stream into the CustomElementDimensionsProvider.
-      final CustomElementDimensionsProvider provider =
-          CustomElementDimensionsProvider(
-        sizeSource,
-        onDprChange: dprController.stream,
-      );
-
-      // Set and broadcast the mock DPR value
-      EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(3.2);
-      dprController.add(3.2);
-
-      expect(provider.onResize.first, completes);
-      expect(provider.computePhysicalSize(), const ui.Size(32, 32));
+      expect(await provider.onResize.first, const ui.Size(300, 300));
     });
 
     test('closed by onHotRestart', () async {

lib/web_ui/test/engine/view_embedder/dimensions_provider/custom_element_dimensions_provider_test.dart

@@ -2,6 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+@TestOn('browser')
+library;
+
 import 'package:test/bootstrap/browser.dart';
 import 'package:test/test.dart';
 import 'package:ui/src/engine.dart';
@@ -28,4 +31,15 @@ void doTests() {
       expect(provider, isA<CustomElementDimensionsProvider>());
     });
   });
+
+  group('getDevicePixelRatio', () {
+    test('Returns the correct pixelRatio', () async {
+      // Override the DPI to something known, but weird...
+      EngineFlutterDisplay.instance.debugOverrideDevicePixelRatio(33930);
+
+      final DimensionsProvider provider = DimensionsProvider.create();
+
+      expect(provider.getDevicePixelRatio(), 33930);
+    });
+  });
 }