Revert "Introduce the PipelineOwner tree (#122231)" (#122425)

This reverts commit f73c358e.

packages/flutter/lib/src/rendering/binding.dart

@@ -30,6 +30,7 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
     super.initInstances();
     _instance = this;
     _pipelineOwner = PipelineOwner(
+      onNeedVisualUpdate: ensureVisualUpdate,
       onSemanticsOwnerCreated: _handleSemanticsOwnerCreated,
       onSemanticsUpdate: _handleSemanticsUpdate,
       onSemanticsOwnerDisposed: _handleSemanticsOwnerDisposed,
@@ -44,7 +45,8 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
     if (kIsWeb) {
       addPostFrameCallback(_handleWebFirstFrame);
     }
-    _pipelineOwner.attach(_manifold);
+    addSemanticsEnabledListener(_handleSemanticsEnabledChanged);
+    _handleSemanticsEnabledChanged();
   }
 
   /// The current [RendererBinding], if one has been created.
@@ -199,8 +201,6 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
     }
   }
 
-  late final PipelineManifold _manifold = _BindingPipelineManifold(this);
-
   /// Creates a [RenderView] object to be the root of the
   /// [RenderObject] rendering tree, and initializes it so that it
   /// will be rendered when the next frame is requested.
@@ -330,6 +330,17 @@ mixin RendererBinding on BindingBase, ServicesBinding, SchedulerBinding, Gesture
     super.dispatchEvent(event, hitTestResult);
   }
 
+  SemanticsHandle? _semanticsHandle;
+
+  void _handleSemanticsEnabledChanged() {
+    if (semanticsEnabled) {
+      _semanticsHandle ??= _pipelineOwner.ensureSemantics();
+    } else {
+      _semanticsHandle?.dispose();
+      _semanticsHandle = null;
+    }
+  }
+
   @override
   void performSemanticsAction(SemanticsActionEvent action) {
     _pipelineOwner.semanticsOwner?.performAction(action.nodeId, action.type, action.arguments);
@@ -610,26 +621,3 @@ class RenderingFlutterBinding extends BindingBase with GestureBinding, Scheduler
     return RendererBinding.instance;
   }
 }
-
-/// A [PipelineManifold] implementation that is backed by the [RendererBinding].
-class _BindingPipelineManifold extends ChangeNotifier implements PipelineManifold {
-  _BindingPipelineManifold(this._binding) {
-    _binding.addSemanticsEnabledListener(notifyListeners);
-  }
-
-  final RendererBinding _binding;
-
-  @override
-  void requestVisualUpdate() {
-    _binding.ensureVisualUpdate();
-  }
-
-  @override
-  bool get semanticsEnabled => _binding.semanticsEnabled;
-
-  @override
-  void dispose() {
-    _binding.removeSemanticsEnabledListener(notifyListeners);
-    super.dispose();
-  }
-}

packages/flutter/test/rendering/binding_pipeline_manifold_init_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 'package:flutter/rendering.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-void main() {
-  test('Initializing the RendererBinding does not crash when semantics is enabled', () {
-    try {
-      MyRenderingFlutterBinding();
-    } catch (e) {
-      fail('Initializing the RenderingBinding threw an unexpected error:\n$e');
-    }
-    expect(RendererBinding.instance, isA<MyRenderingFlutterBinding>());
-    expect(SemanticsBinding.instance.semanticsEnabled, isTrue);
-  });
-}
-
-// Binding that pretends the platform had semantics enabled before the binding
-// is initialized.
-class MyRenderingFlutterBinding extends RenderingFlutterBinding {
-  @override
-  bool get semanticsEnabled => true;
-}

packages/flutter/test/rendering/binding_pipeline_manifold_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 'package:flutter/foundation.dart';
-import 'package:flutter/rendering.dart';
-import 'package:flutter_test/flutter_test.dart';
-
-import 'rendering_tester.dart';
-
-void main() {
-  MyTestRenderingFlutterBinding.ensureInitialized();
-
-  tearDown(() {
-    final List<PipelineOwner> children = <PipelineOwner>[];
-    RendererBinding.instance.pipelineOwner.visitChildren((PipelineOwner child) {
-      children.add(child);
-    });
-    children.forEach(RendererBinding.instance.pipelineOwner.dropChild);
-  });
-
-  test("BindingPipelineManifold notifies binding if render object managed by binding's PipelineOwner tree needs visual update", () {
-    final PipelineOwner child = PipelineOwner();
-    RendererBinding.instance.pipelineOwner.adoptChild(child);
-
-    final RenderObject renderObject = TestRenderObject();
-    child.rootNode = renderObject;
-    renderObject.scheduleInitialLayout();
-    RendererBinding.instance.pipelineOwner.flushLayout();
-
-    MyTestRenderingFlutterBinding.instance.ensureVisualUpdateCount = 0;
-    renderObject.markNeedsLayout();
-    expect(MyTestRenderingFlutterBinding.instance.ensureVisualUpdateCount, 1);
-  });
-
-  test('Turning global semantics on/off creates semantics owners in PipelineOwner tree', () {
-    final PipelineOwner child = PipelineOwner(
-      onSemanticsUpdate: (_) { },
-    );
-    RendererBinding.instance.pipelineOwner.adoptChild(child);
-
-    expect(child.semanticsOwner, isNull);
-    expect(RendererBinding.instance.pipelineOwner.semanticsOwner, isNull);
-
-    final SemanticsHandle handle = SemanticsBinding.instance.ensureSemantics();
-
-    expect(child.semanticsOwner, isNotNull);
-    expect(RendererBinding.instance.pipelineOwner.semanticsOwner, isNotNull);
-
-    handle.dispose();
-
-    expect(child.semanticsOwner, isNull);
-    expect(RendererBinding.instance.pipelineOwner.semanticsOwner, isNull);
-  });
-}
-
-class MyTestRenderingFlutterBinding extends TestRenderingFlutterBinding {
-  static MyTestRenderingFlutterBinding get instance => BindingBase.checkInstance(_instance);
-  static MyTestRenderingFlutterBinding? _instance;
-
-  static MyTestRenderingFlutterBinding ensureInitialized() {
-    if (_instance != null) {
-      return _instance!;
-    }
-    return MyTestRenderingFlutterBinding();
-  }
-
-  @override
-  void initInstances() {
-    super.initInstances();
-    _instance = this;
-  }
-
-  int ensureVisualUpdateCount = 0;
-
-  @override
-  void ensureVisualUpdate() {
-    super.ensureVisualUpdate();
-    ensureVisualUpdateCount++;
-  }
-}
-
-class TestRenderObject extends RenderObject {
-  @override
-  void debugAssertDoesMeetConstraints() { }
-
-  @override
-  Rect get paintBounds => Rect.zero;
-
-  @override
-  void performLayout() { }
-
-  @override
-  void performResize() { }
-
-  @override
-  Rect get semanticBounds => Rect.zero;
-}

packages/flutter_test/lib/src/widget_tester.dart

@@ -1045,7 +1045,7 @@ class WidgetTester extends WidgetController implements HitTestDispatcher, Ticker
   void _verifySemanticsHandlesWereDisposed() {
     assert(_lastRecordedSemanticsHandles != null);
     // TODO(goderbauer): Fix known leak in web engine when running integration tests and remove this "correction", https://github.com/flutter/flutter/issues/121640.
-    final int knownWebEngineLeakForLiveTestsCorrection = kIsWeb && binding is LiveTestWidgetsFlutterBinding ? 1 : 0;
+    final int knownWebEngineLeakForLiveTestsCorrection = kIsWeb && binding is LiveTestWidgetsFlutterBinding ? 2 : 0;
 
     if (_currentSemanticsHandles - knownWebEngineLeakForLiveTestsCorrection > _lastRecordedSemanticsHandles!) {
       throw FlutterError.fromParts(<DiagnosticsNode>[