diff --git a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/scrollable.dart b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/scrollable.dart
index 08e96af35da..44beba5ae99 100644
--- a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/scrollable.dart
+++ b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/scrollable.dart
@@ -70,7 +70,6 @@ class SemanticScrollable extends SemanticRole {
       final bool doScrollForward = _domScrollPosition > _effectiveNeutralScrollPosition;
       _neutralizeDomScrollPosition();
       semanticsObject.recomputePositionAndSize();
-      semanticsObject.updateChildrenPositionAndSize();
 
       final int semanticsId = semanticsObject.id;
       if (doScrollForward) {
@@ -132,7 +131,6 @@ class SemanticScrollable extends SemanticRole {
     semanticsObject.owner.addOneTimePostUpdateCallback(() {
       _neutralizeDomScrollPosition();
       semanticsObject.recomputePositionAndSize();
-      semanticsObject.updateChildrenPositionAndSize();
     });
 
     if (_scrollListener == null) {
@@ -205,8 +203,8 @@ class SemanticScrollable extends SemanticRole {
       // Read back because the effective value depends on the amount of content.
       _effectiveNeutralScrollPosition = element.scrollTop.toInt();
       semanticsObject
-        ..verticalScrollAdjustment = _effectiveNeutralScrollPosition.toDouble()
-        ..horizontalScrollAdjustment = 0.0;
+        ..verticalContainerAdjustment = _effectiveNeutralScrollPosition.toDouble()
+        ..horizontalContainerAdjustment = 0.0;
     } else {
       // Place the _scrollOverflowElement at the end of the content and
       // make sure that when we neutralize the scrolling position,
@@ -221,8 +219,8 @@ class SemanticScrollable extends SemanticRole {
       // Read back because the effective value depends on the amount of content.
       _effectiveNeutralScrollPosition = element.scrollLeft.toInt();
       semanticsObject
-        ..verticalScrollAdjustment = 0.0
-        ..horizontalScrollAdjustment = _effectiveNeutralScrollPosition.toDouble();
+        ..verticalContainerAdjustment = 0.0
+        ..horizontalContainerAdjustment = _effectiveNeutralScrollPosition.toDouble();
     }
   }
 
diff --git a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart
index a2c3aae0abf..4e23e4baf67 100644
--- a/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart
+++ b/engine/src/flutter/lib/web_ui/lib/src/engine/semantics/semantics.dart
@@ -1358,6 +1358,33 @@ class SemanticsObject {
   /// The dom element of this semantics object.
   DomElement get element => semanticRole!.element;
 
+  /// Returns the HTML element that contains the HTML elements of direct
+  /// children of this object.
+  ///
+  /// The element is created lazily. When the child list is empty this element
+  /// is not created. This is necessary for "aria-label" to function correctly.
+  /// The browser will ignore the [label] of HTML element that contain child
+  /// elements.
+  DomElement? getOrCreateChildContainer() {
+    if (_childContainerElement == null) {
+      _childContainerElement = createDomElement('flt-semantics-container');
+      _childContainerElement!.style
+        ..position = 'absolute'
+        // Ignore pointer events on child container so that platform views
+        // behind it can be reached.
+        ..pointerEvents = 'none';
+      element.append(_childContainerElement!);
+    }
+    return _childContainerElement;
+  }
+
+  /// The element that contains the elements belonging to the child semantics
+  /// nodes.
+  ///
+  /// This element is used to correct for [_rect] offsets. It is only non-`null`
+  /// when there are non-zero children (i.e. when [hasChildren] is `true`).
+  DomElement? _childContainerElement;
+
   /// The parent of this semantics object.
   ///
   /// This value is not final until the tree is finalized. It is not safe to
@@ -1655,15 +1682,22 @@ class SemanticsObject {
     // Trivial case: remove all children.
     if (_childrenInHitTestOrder == null || _childrenInHitTestOrder!.isEmpty) {
       if (_currentChildrenInRenderOrder == null || _currentChildrenInRenderOrder!.isEmpty) {
+        // A container element must not have been created when child list is empty.
+        assert(_childContainerElement == null);
         _currentChildrenInRenderOrder = null;
         return;
       }
 
+      // A container element must have been created when child list is not empty.
+      assert(_childContainerElement != null);
+
       // Remove all children from this semantics object.
       final int len = _currentChildrenInRenderOrder!.length;
       for (int i = 0; i < len; i++) {
         owner._detachObject(_currentChildrenInRenderOrder![i].id);
       }
+      _childContainerElement!.remove();
+      _childContainerElement = null;
       _currentChildrenInRenderOrder = null;
       return;
     }
@@ -1672,6 +1706,7 @@ class SemanticsObject {
     final Int32List childrenInTraversalOrder = _childrenInTraversalOrder!;
     final Int32List childrenInHitTestOrder = _childrenInHitTestOrder!;
     final int childCount = childrenInHitTestOrder.length;
+    final DomElement? containerElement = getOrCreateChildContainer();
 
     assert(childrenInTraversalOrder.length == childrenInHitTestOrder.length);
 
@@ -1703,7 +1738,7 @@ class SemanticsObject {
     // Trivial case: previous list was empty => just populate the container.
     if (_currentChildrenInRenderOrder == null || _currentChildrenInRenderOrder!.isEmpty) {
       for (final SemanticsObject child in childrenInRenderOrder) {
-        element.append(child.element);
+        containerElement!.append(child.element);
         owner._attachObject(parent: this, child: child);
       }
       _currentChildrenInRenderOrder = childrenInRenderOrder;
@@ -1787,9 +1822,9 @@ class SemanticsObject {
       final SemanticsObject child = childrenInRenderOrder[i];
       if (!stationaryIds.contains(child.id)) {
         if (refNode == null) {
-          element.append(child.element);
+          containerElement!.append(child.element);
         } else {
-          element.insertBefore(child.element, refNode);
+          containerElement!.insertBefore(child.element, refNode);
         }
         owner._attachObject(parent: this, child: child);
       } else {
@@ -1955,6 +1990,10 @@ class SemanticsObject {
 
     // Reparent element.
     if (previousElement != element) {
+      final DomElement? container = _childContainerElement;
+      if (container != null) {
+        element.append(container);
+      }
       final DomElement? parent = previousElement?.parent;
       if (parent != null) {
         parent.insertBefore(element, previousElement);
@@ -2040,74 +2079,60 @@ class SemanticsObject {
   /// Indicates whether the node is currently expanded.
   bool get isExpanded => hasFlag(ui.SemanticsFlag.isExpanded);
 
-  /// Role-specific adjustment of the vertical position of the children.
+  /// Role-specific adjustment of the vertical position of the child container.
   ///
   /// This is used, for example, by the [SemanticScrollable] to compensate for the
   /// `scrollTop` offset in the DOM.
   ///
   /// This field must not be null.
-  double verticalScrollAdjustment = 0.0;
+  double verticalContainerAdjustment = 0.0;
 
-  /// Role-specific adjustment of the horizontal position of children.
+  /// Role-specific adjustment of the horizontal position of the child
+  /// container.
   ///
   /// This is used, for example, by the [SemanticScrollable] to compensate for the
   /// `scrollLeft` offset in the DOM.
   ///
   /// This field must not be null.
-  double horizontalScrollAdjustment = 0.0;
-
-  double verticalAdjustmentFromParent = 0.0;
-  double horizontalAdjustmentFromParent = 0.0;
+  double horizontalContainerAdjustment = 0.0;
 
   /// Computes the size and position of [element] and, if this element
-  /// [hasChildren], computes the parent adjustment for each child.
+  /// [hasChildren], of [getOrCreateChildContainer].
   void recomputePositionAndSize() {
     element.style
       ..width = '${_rect!.width}px'
       ..height = '${_rect!.height}px';
 
+    final DomElement? containerElement = hasChildren ? getOrCreateChildContainer() : null;
+
     final bool hasZeroRectOffset = _rect!.top == 0.0 && _rect!.left == 0.0;
     final Float32List? transform = _transform;
     final bool hasIdentityTransform =
         transform == null || isIdentityFloat32ListTransform(transform);
 
-    // If this node has children, we need to compensate for the parent's rect and
-    // pass down the scroll adjustments.
-    if (hasChildren) {
-      final double translateX = -_rect!.left + horizontalScrollAdjustment;
-      final double translateY = -_rect!.top + verticalScrollAdjustment;
-
-      for (final childIndex in _childrenInTraversalOrder!) {
-        final child = owner._semanticsTree[childIndex];
-        if (child == null) {
-          continue;
-        }
-        child.horizontalAdjustmentFromParent = translateX;
-        child.verticalAdjustmentFromParent = translateY;
-      }
-    }
-
     if (hasZeroRectOffset &&
         hasIdentityTransform &&
-        verticalAdjustmentFromParent == 0.0 &&
-        horizontalAdjustmentFromParent == 0.0) {
+        verticalContainerAdjustment == 0.0 &&
+        horizontalContainerAdjustment == 0.0) {
       _clearSemanticElementTransform(element);
+      if (containerElement != null) {
+        _clearSemanticElementTransform(containerElement);
+      }
       return;
     }
 
     late Matrix4 effectiveTransform;
     bool effectiveTransformIsIdentity = true;
-
-    final double left = _rect!.left + horizontalAdjustmentFromParent;
-    final double top = _rect!.top + verticalAdjustmentFromParent;
-
-    if (left != 0.0 || top != 0.0) {
+    if (!hasZeroRectOffset) {
       if (transform == null) {
+        final double left = _rect!.left;
+        final double top = _rect!.top;
         effectiveTransform = Matrix4.translationValues(left, top, 0.0);
-        effectiveTransformIsIdentity = false;
+        effectiveTransformIsIdentity = left == 0.0 && top == 0.0;
       } else {
         // Clone to avoid mutating _transform.
-        effectiveTransform = Matrix4.fromFloat32List(transform).clone()..translate(left, top);
+        effectiveTransform =
+            Matrix4.fromFloat32List(transform).clone()..translate(_rect!.left, _rect!.top);
         effectiveTransformIsIdentity = effectiveTransform.isIdentity();
       }
     } else if (!hasIdentityTransform) {
@@ -2122,16 +2147,19 @@ class SemanticsObject {
     } else {
       _clearSemanticElementTransform(element);
     }
-  }
 
-  /// Computes the size and position of children.
-  void updateChildrenPositionAndSize() {
-    for (final childIndex in _childrenInTraversalOrder!) {
-      final child = owner._semanticsTree[childIndex];
-      if (child == null) {
-        continue;
+    if (containerElement != null) {
+      if (!hasZeroRectOffset ||
+          verticalContainerAdjustment != 0.0 ||
+          horizontalContainerAdjustment != 0.0) {
+        final double translateX = -_rect!.left + horizontalContainerAdjustment;
+        final double translateY = -_rect!.top + verticalContainerAdjustment;
+        containerElement.style
+          ..top = '${translateY}px'
+          ..left = '${translateX}px';
+      } else {
+        _clearSemanticElementTransform(containerElement);
       }
-      child.recomputePositionAndSize();
     }
   }
 
@@ -2691,7 +2719,7 @@ class EngineSemanticsOwner {
           removals.add(node);
         } else {
           assert(node._parent == parent);
-          assert(node.element.parentNode == parent.element);
+          assert(node.element.parentNode == parent._childContainerElement);
         }
         return true;
       });
@@ -2800,9 +2828,6 @@ class EngineSemanticsOwner {
       final SemanticsObject object = _semanticsTree[nodeUpdate.id]!;
       object.updateChildren();
       object._dirtyFields = 0;
-
-      object.recomputePositionAndSize();
-      object.updateChildrenPositionAndSize();
     }
 
     final SemanticsObject root = _semanticsTree[0]!;
@@ -2838,6 +2863,9 @@ AFTER: $description
         // Dirty fields should be cleared after the tree has been finalized.
         assert(object._dirtyFields == 0);
 
+        // Make sure a child container is created only when there are children.
+        assert(object._childContainerElement == null || object.hasChildren);
+
         // Ensure child ID list is consistent with the parent-child
         // relationship of the semantics tree.
         if (object._childrenInTraversalOrder != null) {
diff --git a/engine/src/flutter/lib/web_ui/test/common/matchers.dart b/engine/src/flutter/lib/web_ui/test/common/matchers.dart
index e12d1a90251..7537b40cfd8 100644
--- a/engine/src/flutter/lib/web_ui/test/common/matchers.dart
+++ b/engine/src/flutter/lib/web_ui/test/common/matchers.dart
@@ -274,6 +274,7 @@ class HtmlPatternMatcher extends Matcher {
   static bool _areTagsEqual(html.Element a, html.Element b) {
     const Map<String, String> synonyms = <String, String>{
       'sem': 'flt-semantics',
+      'sem-c': 'flt-semantics-container',
       'sem-img': 'flt-semantics-img',
       'sem-tf': 'flt-semantics-text-field',
     };
diff --git a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_multi_view_test.dart b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_multi_view_test.dart
index 8fce7b62e99..676c41d8b21 100644
--- a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_multi_view_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_multi_view_test.dart
@@ -99,11 +99,15 @@ Future<void> testMain() async {
     // Test that each view renders its own semantics tree.
     expectSemanticsTree(view1.semantics, '''
 <sem style="filter: opacity(0%); color: rgba(0, 0, 0, 0)">
+  <sem-c>
     <sem flt-tappable="" role="button"></sem>
+  </sem-c>
 </sem>''');
     expectSemanticsTree(view2.semantics, '''
 <sem style="filter: opacity(0%); color: rgba(0, 0, 0, 0)">
+  <sem-c>
     <sem aria-label="d"><input aria-valuemax="1" aria-valuemin="1" aria-valuenow="1" aria-valuetext="" role="slider"></sem>
+  </sem-c>
 </sem>
 ''');
 
diff --git a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_test.dart b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_test.dart
index ba593ca8d66..ce9d9db01ac 100644
--- a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_test.dart
@@ -158,8 +158,10 @@ void _testSemanticRole() {
 
     tester.expectSemantics('''
 <sem id="flt-semantic-node-0">
+  <sem-c>
     <sem id="flt-semantic-node-372"></sem>
     <sem id="flt-semantic-node-599"></sem>
+  </sem-c>
 </sem>''');
 
     tester.updateNode(
@@ -173,8 +175,10 @@ void _testSemanticRole() {
 
     tester.expectSemantics('''
 <sem id="flt-semantic-node-0">
+  <sem-c>
     <sem id="flt-semantic-node-372" flt-semantics-identifier="test-id-123"></sem>
     <sem id="flt-semantic-node-599"></sem>
+  </sem-c>
 </sem>''');
 
     tester.updateNode(
@@ -189,9 +193,11 @@ void _testSemanticRole() {
 
     tester.expectSemantics('''
 <sem id="flt-semantic-node-0">
+  <sem-c>
     <sem id="flt-semantic-node-372"></sem>
     <sem id="flt-semantic-node-599" flt-semantics-identifier="test-id-211"></sem>
     <sem id="flt-semantic-node-612" flt-semantics-identifier="test-id-333"></sem>
+  </sem-c>
 </sem>''');
   });
 }
@@ -514,7 +520,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>Hello</span></sem>
+  </sem-c>
 </sem>''');
 
     // Update
@@ -522,7 +530,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>World</span></sem>
+  </sem-c>
 </sem>''');
 
     // Remove
@@ -530,7 +540,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     semantics().semanticsEnabled = false;
@@ -551,7 +563,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>Hello</span></sem>
+  </sem-c>
 </sem>''');
 
     // Update
@@ -564,7 +578,9 @@ void _testEngineSemanticsOwner() {
     expect(tree[1]!.element.tagName.toLowerCase(), 'a');
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <a style="display: block;">Hello</a>
+  </sem-c>
 </sem>''');
     expect(existingParent, tree[1]!.element.parent);
 
@@ -586,7 +602,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>tooltip</span></sem>
+  </sem-c>
 </sem>''');
 
     // Update
@@ -594,7 +612,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>tooltip\nHello</span></sem>
+  </sem-c>
 </sem>''');
 
     // Remove
@@ -602,7 +622,9 @@ void _testEngineSemanticsOwner() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     semantics().semanticsEnabled = false;
@@ -827,7 +849,7 @@ void _testHeader() {
 
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
-<header aria-label="Header of the page"><sem></sem></header>
+<header aria-label="Header of the page"><sem-c><sem></sem></sem-c></header>
 ''');
 
     semantics().semanticsEnabled = false;
@@ -934,7 +956,7 @@ label hint''');
 }
 
 void _testContainer() {
-  test('child node has no transform when there is no rect offset', () async {
+  test('container node has no transform when there is no rect offset', () async {
     semantics()
       ..debugOverrideTimestampFunction(() => _testTime)
       ..semanticsEnabled = true;
@@ -951,30 +973,35 @@ void _testContainer() {
     updateNode(builder, id: 1, transform: Matrix4.identity().toFloat64(), rect: zeroOffsetRect);
 
     owner().updateSemantics(builder.build());
-    expectSemanticsTree(owner(), '''<sem><sem></sem></sem>''');
+    expectSemanticsTree(owner(), '''
+<sem>
+  <sem-c>
+    <sem></sem>
+  </sem-c>
+</sem>''');
 
     final DomElement parentElement = owner().semanticsHost.querySelector('flt-semantics')!;
-    final DomElement childElement = owner().semanticsHost.querySelector('#flt-semantic-node-1')!;
+    final DomElement container = owner().semanticsHost.querySelector('flt-semantics-container')!;
 
     if (isMacOrIOS) {
       expect(parentElement.style.top, '0px');
       expect(parentElement.style.left, '0px');
-      expect(childElement.style.top, '0px');
-      expect(childElement.style.left, '0px');
+      expect(container.style.top, '0px');
+      expect(container.style.left, '0px');
     } else {
       expect(parentElement.style.top, '');
       expect(parentElement.style.left, '');
-      expect(childElement.style.top, '');
-      expect(childElement.style.left, '');
+      expect(container.style.top, '');
+      expect(container.style.left, '');
     }
     expect(parentElement.style.transform, '');
     expect(parentElement.style.transformOrigin, '');
-    expect(childElement.style.transform, '');
-    expect(childElement.style.transformOrigin, '');
+    expect(container.style.transform, '');
+    expect(container.style.transformOrigin, '');
     semantics().semanticsEnabled = false;
   });
 
-  test('child node transform compensates for parent rect offset', () async {
+  test('container node compensates for rect offset', () async {
     semantics()
       ..debugOverrideTimestampFunction(() => _testTime)
       ..semanticsEnabled = true;
@@ -991,14 +1018,19 @@ void _testContainer() {
       builder,
       id: 1,
       transform: Matrix4.identity().toFloat64(),
-      rect: const ui.Rect.fromLTRB(0, 0, 5, 5),
+      rect: const ui.Rect.fromLTRB(10, 10, 20, 20),
     );
 
     owner().updateSemantics(builder.build());
-    expectSemanticsTree(owner(), '''<sem><sem></sem></sem>''');
+    expectSemanticsTree(owner(), '''
+<sem>
+  <sem-c>
+    <sem></sem>
+  </sem-c>
+</sem>''');
 
     final DomElement parentElement = owner().semanticsHost.querySelector('flt-semantics')!;
-    final DomElement childElement = owner().semanticsHost.querySelector('#flt-semantic-node-1')!;
+    final DomElement container = owner().semanticsHost.querySelector('flt-semantics-container')!;
 
     expect(parentElement.style.transform, 'matrix(1, 0, 0, 1, 10, 10)');
     if (isSafari) {
@@ -1007,103 +1039,63 @@ void _testContainer() {
         parentElement.style.transformOrigin,
         anyOf(contains('0px 0px 0px'), contains('0px 0px')),
       );
-      expect(
-        childElement.style.transformOrigin,
-        anyOf(contains('0px 0px 0px'), contains('0px 0px')),
-      );
     } else {
       expect(parentElement.style.transformOrigin, '0px 0px 0px');
-      expect(childElement.style.transformOrigin, '0px 0px 0px');
     }
-    expect(childElement.style.transform, 'matrix(1, 0, 0, 1, -10, -10)');
-    expect(childElement.style.left == '0px' || childElement.style.left == '', isTrue);
-    expect(childElement.style.top == '0px' || childElement.style.top == '', isTrue);
-
+    expect(container.style.top, '-10px');
+    expect(container.style.left, '-10px');
     semantics().semanticsEnabled = false;
   });
 
-  test(
-    'child node transform compensates for parent rect offset when parent rect changed',
-    () async {
-      semantics()
-        ..debugOverrideTimestampFunction(() => _testTime)
-        ..semanticsEnabled = true;
+  test('0 offsets are not removed for voiceover', () async {
+    semantics()
+      ..debugOverrideTimestampFunction(() => _testTime)
+      ..semanticsEnabled = true;
 
-      final ui.SemanticsUpdateBuilder builder = ui.SemanticsUpdateBuilder();
-      updateNode(
-        builder,
-        transform: Matrix4.identity().toFloat64(),
-        rect: const ui.Rect.fromLTRB(10, 10, 20, 20),
-        childrenInHitTestOrder: Int32List.fromList(<int>[1]),
-        childrenInTraversalOrder: Int32List.fromList(<int>[1]),
-      );
-      updateNode(
-        builder,
-        id: 1,
-        transform: Matrix4.identity().toFloat64(),
-        rect: const ui.Rect.fromLTRB(0, 0, 5, 5),
-      );
+    final ui.SemanticsUpdateBuilder builder = ui.SemanticsUpdateBuilder();
+    updateNode(
+      builder,
+      transform: Matrix4.identity().toFloat64(),
+      rect: const ui.Rect.fromLTRB(0, 0, 20, 20),
+      childrenInHitTestOrder: Int32List.fromList(<int>[1]),
+      childrenInTraversalOrder: Int32List.fromList(<int>[1]),
+    );
+    updateNode(
+      builder,
+      id: 1,
+      transform: Matrix4.identity().toFloat64(),
+      rect: const ui.Rect.fromLTRB(10, 10, 20, 20),
+    );
 
-      owner().updateSemantics(builder.build());
-      expectSemanticsTree(owner(), '''<sem><sem></sem></sem>''');
+    owner().updateSemantics(builder.build());
+    expectSemanticsTree(owner(), '''
+<sem>
+  <sem-c>
+    <sem></sem>
+  </sem-c>
+</sem>''');
 
-      final DomElement parentElement = owner().semanticsHost.querySelector('flt-semantics')!;
-      final DomElement childElement = owner().semanticsHost.querySelector('#flt-semantic-node-1')!;
+    final DomElement parentElement = owner().semanticsHost.querySelector('flt-semantics')!;
+    final DomElement container = owner().semanticsHost.querySelector('flt-semantics-container')!;
 
-      expect(parentElement.style.transform, 'matrix(1, 0, 0, 1, 10, 10)');
-      if (isSafari) {
-        // macOS 13 returns different values than macOS 12.
-        expect(
-          parentElement.style.transformOrigin,
-          anyOf(contains('0px 0px 0px'), contains('0px 0px')),
-        );
-        expect(
-          childElement.style.transformOrigin,
-          anyOf(contains('0px 0px 0px'), contains('0px 0px')),
-        );
-      } else {
-        expect(parentElement.style.transformOrigin, '0px 0px 0px');
-        expect(childElement.style.transformOrigin, '0px 0px 0px');
-      }
-      expect(childElement.style.transform, 'matrix(1, 0, 0, 1, -10, -10)');
-      expect(childElement.style.left == '0px' || childElement.style.left == '', isTrue);
-      expect(childElement.style.top == '0px' || childElement.style.top == '', isTrue);
+    if (isMacOrIOS) {
+      expect(parentElement.style.top, '0px');
+      expect(parentElement.style.left, '0px');
+      expect(container.style.top, '0px');
+      expect(container.style.left, '0px');
+    } else {
+      expect(parentElement.style.top, '');
+      expect(parentElement.style.left, '');
+      expect(container.style.top, '');
+      expect(container.style.left, '');
+    }
+    expect(parentElement.style.transform, '');
+    expect(parentElement.style.transformOrigin, '');
+    expect(container.style.transform, '');
+    expect(container.style.transformOrigin, '');
 
-      final ui.SemanticsUpdateBuilder builder2 = ui.SemanticsUpdateBuilder();
-
-      updateNode(
-        builder2,
-        transform: Matrix4.identity().toFloat64(),
-        rect: const ui.Rect.fromLTRB(33, 33, 20, 20),
-        childrenInHitTestOrder: Int32List.fromList(<int>[1]),
-        childrenInTraversalOrder: Int32List.fromList(<int>[1]),
-      );
-
-      owner().updateSemantics(builder2.build());
-      expectSemanticsTree(owner(), '''<sem><sem></sem></sem>''');
-
-      expect(parentElement.style.transform, 'matrix(1, 0, 0, 1, 33, 33)');
-      if (isSafari) {
-        // macOS 13 returns different values than macOS 12.
-        expect(
-          parentElement.style.transformOrigin,
-          anyOf(contains('0px 0px 0px'), contains('0px 0px')),
-        );
-        expect(
-          childElement.style.transformOrigin,
-          anyOf(contains('0px 0px 0px'), contains('0px 0px')),
-        );
-      } else {
-        expect(parentElement.style.transformOrigin, '0px 0px 0px');
-        expect(childElement.style.transformOrigin, '0px 0px 0px');
-      }
-      expect(childElement.style.transform, 'matrix(1, 0, 0, 1, -33, -33)');
-      expect(childElement.style.left == '0px' || childElement.style.left == '', isTrue);
-      expect(childElement.style.top == '0px' || childElement.style.top == '', isTrue);
-
-      semantics().semanticsEnabled = false;
-    },
-  );
+    semantics().semanticsEnabled = false;
+  });
 
   test('renders in traversal order, hit-tests in reverse z-index order', () async {
     semantics()
@@ -1126,10 +1118,12 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 4"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
     }
 
@@ -1144,10 +1138,12 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 4"></sem>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
     }
 
@@ -1162,10 +1158,12 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 1"></sem>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 4"></sem>
+  </sem-c>
 </sem>''');
     }
 
@@ -1180,10 +1178,12 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 4"></sem>
     <sem style="z-index: 1"></sem>
     <sem style="z-index: 3"></sem>
+  </sem-c>
 </sem>''');
     }
 
@@ -1207,8 +1207,10 @@ void _testContainer() {
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement root = owner().semanticsHost.querySelector('#flt-semantic-node-0')!;
@@ -1241,8 +1243,10 @@ void _testContainer() {
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement root = owner().semanticsHost.querySelector('#flt-semantic-node-0')!;
@@ -1250,6 +1254,7 @@ void _testContainer() {
 
     semantics().semanticsEnabled = false;
   });
+
   test('container can be opaque if it is a text field', () async {
     semantics()
       ..debugOverrideTimestampFunction(() => _testTime)
@@ -1269,8 +1274,10 @@ void _testContainer() {
     expectSemanticsTree(owner(), '''
 <sem>
   <input>
+  <sem-c>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement root = owner().semanticsHost.querySelector('#flt-semantic-node-0')!;
@@ -1311,14 +1318,20 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
   <sem>
+    <sem-c>
       <sem style="z-index: 2">
+        <sem-c>
           <sem style="z-index: 2"></sem>
           <sem style="z-index: 1"></sem>
+        </sem-c>
       </sem>
       <sem style="z-index: 1">
+        <sem-c>
           <sem style="z-index: 2"></sem>
           <sem style="z-index: 1"></sem>
+        </sem-c>
       </sem>
+    </sem-c>
   </sem>''');
 
       expect(
@@ -1345,11 +1358,15 @@ void _testContainer() {
       owner().updateSemantics(builder.build());
       expectSemanticsTree(owner(), '''
   <sem>
+    <sem-c>
       <sem style="z-index: 2">
+        <sem-c>
           <sem style="z-index: 3"></sem>
           <sem style="z-index: 2"></sem>
           <sem style="z-index: 1"></sem>
+        </sem-c>
       </sem>
+    </sem-c>
   </sem>''');
 
       expect(owner().debugSemanticsTree!.keys.toList(), unorderedEquals(<int>[0, 1, 3, 4, 6]));
@@ -1435,7 +1452,9 @@ void _testVerticalScrolling() {
     expectSemanticsTree(owner(), '''
 <sem style="touch-action: none; overflow-y: scroll">
 <flt-semantics-scroll-overflow></flt-semantics-scroll-overflow>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement scrollable = findScrollable(owner());
@@ -1489,9 +1508,11 @@ void _testVerticalScrolling() {
     expectSemanticsTree(owner(), '''
 <sem style="touch-action: none; overflow-y: scroll">
   <flt-semantics-scroll-overflow></flt-semantics-scroll-overflow>
+  <sem-c>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement scrollable = owner().debugSemanticsTree![0]!.element;
@@ -1568,9 +1589,11 @@ void _testVerticalScrolling() {
     expectSemanticsTree(owner(), '''
 <sem style="touch-action: none; overflow-y: scroll">
   <flt-semantics-scroll-overflow></flt-semantics-scroll-overflow>
+  <sem-c>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement scrollable = owner().debugSemanticsTree![0]!.element;
@@ -1656,7 +1679,9 @@ void _testHorizontalScrolling() {
     expectSemanticsTree(owner(), '''
 <sem style="touch-action: none; overflow-x: scroll">
 <flt-semantics-scroll-overflow></flt-semantics-scroll-overflow>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement scrollable = findScrollable(owner());
@@ -1710,9 +1735,11 @@ void _testHorizontalScrolling() {
     expectSemanticsTree(owner(), '''
 <sem style="touch-action: none; overflow-x: scroll">
   <flt-semantics-scroll-overflow></flt-semantics-scroll-overflow>
+  <sem-c>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement scrollable = findScrollable(owner());
@@ -2267,8 +2294,10 @@ void _testCheckables() {
 
     expectSemanticsTree(owner(), '''
 <sem role="radiogroup">
+  <sem-c>
     <sem aria-checked="false"></sem>
     <sem aria-checked="true"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2366,9 +2395,11 @@ void _testSelectables() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-selected="false"></sem>
     <sem aria-selected="true"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2393,9 +2424,11 @@ void _testSelectables() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-selected="true"></sem>
     <sem aria-selected="false"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2460,9 +2493,11 @@ void _testExpandables() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-expanded="false"></sem>
     <sem aria-expanded="true"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2487,9 +2522,11 @@ void _testExpandables() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-expanded="true"></sem>
     <sem aria-expanded="false"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2743,7 +2780,9 @@ void _testTappable() {
 
     expectSemanticsTree(owner(), '''
 <sem flt-tappable role="button">
+  <sem-c>
     <sem flt-tappable role="button"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -2834,7 +2873,9 @@ void _testImage() {
     expectSemanticsTree(owner(), '''
 <sem>
   <sem-img role="img" aria-label="Test Image Label"></sem-img>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     semantics().semanticsEnabled = false;
@@ -2884,7 +2925,9 @@ void _testImage() {
     expectSemanticsTree(owner(), '''
 <sem>
   <sem-img role="img"></sem-img>
+  <sem-c>
     <sem></sem>
+  </sem-c>
 </sem>''');
 
     semantics().semanticsEnabled = false;
@@ -3101,9 +3144,11 @@ void _testPlatformView() {
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem style="z-index: 3"></sem>
     <sem style="z-index: 2" aria-owns="flt-pv-0"></sem>
     <sem style="z-index: 1"></sem>
+  </sem-c>
 </sem>''');
 
     final DomElement root = owner().semanticsHost.querySelector('#flt-semantic-node-0')!;
@@ -3197,7 +3242,7 @@ void _testGroup() {
 
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
-<sem role="group" aria-label="this is a label for a group of elements"><sem></sem></sem>
+<sem role="group" aria-label="this is a label for a group of elements"><sem-c><sem></sem></sem-c></sem>
 ''');
 
     semantics().semanticsEnabled = false;
@@ -3229,7 +3274,7 @@ void _testRoute() {
 
     owner().updateSemantics(builder.build());
     expectSemanticsTree(owner(), '''
-      <sem role="dialog" aria-label="this is a route label"><sem></sem></sem>
+      <sem role="dialog" aria-label="this is a route label"><sem-c><sem></sem></sem-c></sem>
     ''');
 
     expect(owner().debugSemanticsTree![0]!.semanticRole?.kind, EngineSemanticsRole.route);
@@ -3268,7 +3313,7 @@ void _testRoute() {
 
     // But still sets the dialog role.
     expectSemanticsTree(owner(), '''
-      <sem role="dialog" aria-label=""><sem></sem></sem>
+      <sem role="dialog" aria-label=""><sem-c><sem></sem></sem-c></sem>
     ''');
 
     expect(owner().debugSemanticsTree![0]!.semanticRole?.kind, EngineSemanticsRole.route);
@@ -3300,9 +3345,13 @@ void _testRoute() {
 
       expectSemanticsTree(owner(), '''
         <sem role="dialog" aria-describedby="flt-semantic-node-2">
+          <sem-c>
             <sem>
+              <sem-c>
                 <sem><span>$label</span></sem>
+              </sem-c>
             </sem>
+          </sem-c>
         </sem>
       ''');
     }
@@ -3362,9 +3411,13 @@ void _testRoute() {
 
     expectSemanticsTree(owner(), '''
       <sem>
+        <sem-c>
           <sem>
+            <sem-c>
               <sem><span>Hello</span></sem>
+            </sem-c>
           </sem>
+        </sem-c>
       </sem>
     ''');
 
@@ -3541,12 +3594,16 @@ void _testRoute() {
 
     tester.expectSemantics('''
 <flt-semantics>
+  <flt-semantics-container>
     <flt-semantics>
+      <flt-semantics-container>
         <flt-semantics id="flt-semantic-node-2">
           <span tabindex="-1">Heading</span>
         </flt-semantics>
         <flt-semantics role="button" tabindex="0" flt-tappable="">Click me!</flt-semantics>
+      </flt-semantics-container>
     </flt-semantics>
+  </flt-semantics-container>
 </flt-semantics>''');
 
     final DomElement span = owner().debugSemanticsTree![2]!.element.querySelectorAll('span').single;
@@ -3646,9 +3703,13 @@ void _testDialogs() {
 
       expectSemanticsTree(owner(), '''
         <sem role="dialog" aria-describedby="flt-semantic-node-2">
+          <sem-c>
             <sem>
+              <sem-c>
                 <sem><span>$label</span></sem>
+              </sem-c>
             </sem>
+          </sem-c>
         </sem>
       ''');
     }
@@ -3807,7 +3868,9 @@ void _testFocusable() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem><span>focusable text</span></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -4198,9 +4261,11 @@ void _testRequirable() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-required="false"></sem>
     <sem aria-required="true"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -4225,9 +4290,11 @@ void _testRequirable() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem aria-required="true"></sem>
     <sem aria-required="false"></sem>
+  </sem-c>
 </sem>
 ''');
 
@@ -4238,9 +4305,11 @@ void _testRequirable() {
 
     expectSemanticsTree(owner(), '''
 <sem>
+  <sem-c>
     <sem></sem>
     <sem></sem>
     <sem></sem>
+  </sem-c>
 </sem>
 ''');
 
diff --git a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_text_test.dart b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_text_test.dart
index 12cb5619f8f..ccb7aec643e 100644
--- a/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_text_test.dart
+++ b/engine/src/flutter/lib/web_ui/test/engine/semantics/semantics_text_test.dart
@@ -110,7 +110,9 @@ Future<void> testMain() async {
 
     expectSemanticsTree(owner(), '''
       <sem aria-label="I am a parent" role="group">
+        <sem-c>
           <sem><span>I am a child</span></sem>
+        </sem-c>
       </sem>''');
 
     semantics().semanticsEnabled = false;
@@ -157,7 +159,9 @@ Future<void> testMain() async {
 
       expectSemanticsTree(owner(), '''
         <sem aria-label="I am a parent" role="group">
+          <sem-c>
             <sem><span>I am a child</span></sem>
+          </sem-c>
         </sem>''');
     }