Revert "Fix RefreshIndicator performance issue (#47667)" (#53149)

This reverts commit 602ac0bc10c9783c4bb94ba8583ee2765a3cc313.

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

@@ -409,26 +409,26 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
     return _pendingRefreshFuture;
   }
 
+  final GlobalKey _key = GlobalKey();
+
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterialLocalizations(context));
     final Widget child = NotificationListener<ScrollNotification>(
+      key: _key,
       onNotification: _handleScrollNotification,
       child: NotificationListener<OverscrollIndicatorNotification>(
         onNotification: _handleGlowNotification,
         child: widget.child,
       ),
     );
-    assert(() {
     if (_mode == null) {
       assert(_dragOffset == null);
       assert(_isIndicatorAtTop == null);
-      } else {
+      return child;
+    }
     assert(_dragOffset != null);
     assert(_isIndicatorAtTop != null);
-      }
-      return true;
-    }());
 
     final bool showIndeterminateIndicator =
       _mode == _RefreshIndicatorMode.refresh || _mode == _RefreshIndicatorMode.done;
@@ -436,7 +436,7 @@ class RefreshIndicatorState extends State<RefreshIndicator> with TickerProviderS
     return Stack(
       children: <Widget>[
         child,
-        if (_mode != null) Positioned(
+        Positioned(
           top: _isIndicatorAtTop ? 0.0 : null,
           bottom: !_isIndicatorAtTop ? 0.0 : null,
           left: 0.0,

packages/flutter/test/material/refresh_indicator_test.dart

@@ -420,39 +420,4 @@ void main() {
     expect(controller.offset, lessThan(0.0));
     expect(refreshCalled, isTrue);
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
-
-  testWidgets('RefreshIndicator does not force child to relayout', (WidgetTester tester) async {
-    int layoutCount = 0;
-
-    Widget layoutCallback(BuildContext context, BoxConstraints constraints) {
-      layoutCount++;
-      return ListView(
-        physics: const AlwaysScrollableScrollPhysics(),
-        children: <String>['A', 'B', 'C', 'D', 'E', 'F'].map<Widget>((String item) {
-          return SizedBox(
-            height: 200.0,
-            child: Text(item),
-          );
-        }).toList(),
-      );
-    }
-
-    await tester.pumpWidget(
-      MaterialApp(
-        home: RefreshIndicator(
-          onRefresh: refresh,
-          child: LayoutBuilder(builder: layoutCallback),
-        ),
-      ),
-    );
-
-    await tester.fling(find.text('A'), const Offset(0.0, 300.0), 1000.0); // trigger refresh
-    await tester.pump();
-
-    await tester.pump(const Duration(seconds: 1)); // finish the scroll animation
-    await tester.pump(const Duration(seconds: 1)); // finish the indicator settle animation
-    await tester.pump(const Duration(seconds: 1)); // finish the indicator hide animation
-
-    expect(layoutCount, 1);
-  });
 }