Allow `OverlayPortal` to be added/removed from the tree in a layout callback (#130670)

Fixes https://github.com/flutter/flutter/issues/130668

packages/flutter/lib/src/widgets/overlay.dart

@@ -936,14 +936,6 @@ class _RenderTheater extends RenderBox with ContainerRenderObjectMixin<RenderBox
   @override
   void redepthChildren() => visitChildren(redepthChild);
 
-  void _adoptDeferredLayoutBoxChild(_RenderDeferredLayoutBox child) {
-    adoptChild(child);
-  }
-
-  void _dropDeferredLayoutBoxChild(_RenderDeferredLayoutBox child) {
-    dropChild(child);
-  }
-
   Alignment? _alignmentCache;
   Alignment get _resolvedAlignment => _alignmentCache ??= AlignmentDirectional.topStart.resolve(textDirection);
 
@@ -1704,13 +1696,13 @@ final class _OverlayEntryLocation extends LinkedListEntry<_OverlayEntryLocation>
     // This call is allowed even when this location is invalidated.
     // See _OverlayPortalElement.activate.
     assert(_overlayChildRenderBox == null, '$_overlayChildRenderBox');
-    _theater._adoptDeferredLayoutBoxChild(child);
+    _theater._addDeferredChild(child);
     _overlayChildRenderBox = child;
   }
 
   void _deactivate(_RenderDeferredLayoutBox child) {
     // This call is allowed even when this location is invalidated.
-    _theater._dropDeferredLayoutBoxChild(child);
+    _theater._removeDeferredChild(child);
     _overlayChildRenderBox = null;
   }
 

packages/flutter/test/widgets/overlay_portal_test.dart

@@ -655,6 +655,63 @@ void main() {
     verifyTreeIsClean();
   });
 
+  testWidgets('Adding/Removing OverlayPortal in LayoutBuilder during layout', (WidgetTester tester) async {
+    final GlobalKey widgetKey = GlobalKey(debugLabel: 'widget');
+    final GlobalKey overlayKey = GlobalKey(debugLabel: 'overlay');
+    controller1.hide();
+    late StateSetter setState;
+    Size size = Size.zero;
+
+    final Widget overlayPortal = OverlayPortal(
+      key: widgetKey,
+      controller: controller1,
+      overlayChildBuilder: (BuildContext context) => const Placeholder(),
+      child: const Placeholder(),
+    );
+
+    await tester.pumpWidget(
+      Directionality(
+        textDirection: TextDirection.ltr,
+        child: Overlay(
+          key: overlayKey,
+          initialEntries: <OverlayEntry>[
+            OverlayEntry(
+              builder: (BuildContext context) {
+                return StatefulBuilder(
+                  builder: (BuildContext context, StateSetter stateSetter) {
+                    setState = stateSetter;
+                    return Center(
+                      child: SizedBox.fromSize(
+                        size: size,
+                        child: LayoutBuilder(builder: (BuildContext context, BoxConstraints constraints) {
+                          // This layout callback adds/removes an OverlayPortal during layout.
+                          return constraints.maxHeight > 0 ? overlayPortal : const SizedBox();
+                        }),
+                      ),
+                    );
+                  }
+                );
+              }
+            ),
+          ],
+        ),
+      ),
+    );
+    controller1.show();
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+
+    // Adds the OverlayPortal from within a LayoutBuilder, in a layout callback.
+    setState(() { size = const Size(300, 300); });
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+
+    // Removes the OverlayPortal from within a LayoutBuilder, in a layout callback.
+    setState(() { size = Size.zero; });
+    await tester.pump();
+    expect(tester.takeException(), isNull);
+  });
+
   testWidgets('Change overlay constraints', (WidgetTester tester) async {
     final GlobalKey widgetKey = GlobalKey(debugLabel: 'widget outer');
     final GlobalKey overlayKey = GlobalKey(debugLabel: 'overlay');