Revert "Fix ReorderableListView's use of child keys (#41334) (#41338)" (#41931)

This reverts commit 2b138fd7.

packages/flutter/lib/src/material/reorderable_list.dart

@@ -4,9 +4,8 @@
 
 import 'dart:math';
 
-import 'package:flutter/foundation.dart';
-import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
+import 'package:flutter/rendering.dart';
 
 import 'debug.dart';
 import 'material.dart';
@@ -345,11 +344,7 @@ class _ReorderableListContentState extends State<_ReorderableListContent> with T
   // Handles up the logic for dragging and reordering items in the list.
   Widget _wrap(Widget toWrap, int index, BoxConstraints constraints) {
     assert(toWrap.key != null);
-    final _ScopedValueGlobalKey<_ReorderableListContentState> keyIndexGlobalKey =
-        _ScopedValueGlobalKey<_ReorderableListContentState>(
-      scope: this,
-      value: toWrap.key,
-    );
+    final GlobalObjectKey keyIndexGlobalKey = GlobalObjectKey(toWrap.key);
     // We pass the toWrapWithGlobalKey into the Draggable so that when a list
     // item gets dragged, the accessibility framework can preserve the selected
     // state of the dragging item.
@@ -579,32 +574,3 @@ class _ReorderableListContentState extends State<_ReorderableListContent> with T
     });
   }
 }
-
-/// A [GlobalKey] that uses a scope and a value to determine equality.
-///
-/// The scope is compared using [identical], while the value is compared
-/// using [operator ==]. This allows a locally scoped value to be turned
-/// into a globally unique key.
-class _ScopedValueGlobalKey<T extends State<StatefulWidget>> extends GlobalKey<T> {
-  const _ScopedValueGlobalKey({this.scope, this.value}) : super.constructor();
-
-  final Object scope;
-  final Object value;
-
-  @override
-  int get hashCode => hashValues(identityHashCode(scope), value.hashCode);
-
-  @override
-  bool operator ==(dynamic other) {
-    if (other.runtimeType != runtimeType) {
-      return false;
-    }
-    final _ScopedValueGlobalKey<T> typedOther = other;
-    return identical(scope, typedOther.scope) && value == typedOther.value;
-  }
-
-  @override
-  String toString() {
-    return '[$runtimeType ${describeIdentity(scope)} ${describeIdentity(value)}]';
-  }
-}

packages/flutter/test/material/reorderable_list_test.dart

@@ -655,51 +655,6 @@ void main() {
         expect(findState(const Key('A')).checked, true);
       });
 
-      testWidgets('Preserves children states across reorder when keys are not identical', (WidgetTester tester) async {
-        _StatefulState findState(Key key) {
-          return find.byElementPredicate((Element element) => element.ancestorWidgetOfExactType(_Stateful)?.key == key)
-              .evaluate()
-              .first
-              .ancestorStateOfType(const TypeMatcher<_StatefulState>());
-        }
-        await tester.pumpWidget(MaterialApp(
-          home: ReorderableListView(
-            children: <Widget>[
-              _Stateful(key: const ObjectKey('A')),
-              _Stateful(key: const ObjectKey('B')),
-              _Stateful(key: const ObjectKey('C')),
-            ],
-            onReorder: (int oldIndex, int newIndex) { },
-            scrollDirection: Axis.horizontal,
-          ),
-        ));
-        await tester.tap(find.byKey(const ObjectKey('A')));
-        await tester.pumpAndSettle();
-        // Only the 'A' widget should be checked.
-        expect(findState(const ObjectKey('A')).checked, true);
-        expect(findState(const ObjectKey('B')).checked, false);
-        expect(findState(const ObjectKey('C')).checked, false);
-
-        // Rebuild with distinct key objects.
-        await tester.pumpWidget(MaterialApp(
-          home: ReorderableListView(
-            children: <Widget>[
-              // Deliberately avoid the const constructor below to ensure keys are
-              // distinct objects.
-              _Stateful(key: ObjectKey('B')), // ignore:prefer_const_constructors
-              _Stateful(key: ObjectKey('C')), // ignore:prefer_const_constructors
-              _Stateful(key: ObjectKey('A')), // ignore:prefer_const_constructors
-            ],
-            onReorder: (int oldIndex, int newIndex) { },
-            scrollDirection: Axis.horizontal,
-          ),
-        ));
-        // Only the 'A' widget should be checked.
-        expect(findState(const ObjectKey('B')).checked, false);
-        expect(findState(const ObjectKey('C')).checked, false);
-        expect(findState(const ObjectKey('A')).checked, true);
-      });
-
       group('Accessibility (a11y/Semantics)', () {
         Map<CustomSemanticsAction, VoidCallback> getSemanticsActions(int index) {
           final Semantics semantics = find.ancestor(