Revert "ModalRoute resumes previous focus on didPopNext (#33152)" (#33815)

This reverts commit 0f2254a5.

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

@@ -1086,17 +1086,6 @@ abstract class ModalRoute<T> extends TransitionRoute<T> with LocalHistoryRoute<T
     return await super.willPop();
   }
 
-  @override
-  void didPopNext(Route<dynamic> nextRoute) {
-    super.didPopNext(nextRoute);
-    // When the route on top of this route is popped, resume focus onto the
-    // widget that received the last focus.
-    final _ModalScopeState<T> modalScopeState = _scopeKey.currentState;
-    if (modalScopeState != null) {
-      modalScopeState.focusScopeNode.requestFocus();
-    }
-  }
-
   /// Enables this route to veto attempts by the user to dismiss it.
   ///
   /// This callback is typically added using a [WillPopScope] widget. That

packages/flutter/test/material/text_field_focus_test.dart

@@ -40,6 +40,11 @@ void main() {
     Navigator.of(tester.element(find.text('Dialog'))).pop();
     await tester.pump();
 
+    expect(tester.testTextInput.isVisible, isFalse);
+
+    await tester.tap(find.byType(TextField));
+    await tester.idle();
+
     expect(tester.testTextInput.isVisible, isTrue);
 
     await tester.pumpWidget(Container());

packages/flutter/test/widgets/routes_test.dart

@@ -8,7 +8,6 @@ import 'package:flutter/foundation.dart';
 import 'package:mockito/mockito.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
-import 'package:flutter/material.dart';
 
 final List<String> results = <String>[];
 
@@ -504,52 +503,6 @@ void main() {
       verifyNoMoreInteractions(pageRouteAware);
     });
   });
-
-  group('ModalRoute', () {
-    testWidgets('should resume focus when the next route is popped', (WidgetTester tester) async {
-      // TODO(tongmu): It's currently using PageRoute (from MaterialApp)
-      // instead of ModalRoute, which might leave a risk but avoids building
-      // everything from scratch by using the existing setup by MaterialApp and
-      // TextField as a focusable widget. We might want to write a better test.
-
-      final FocusNode node = FocusNode();
-      BuildContext pageContext;
-      final Widget widget = MaterialApp(
-        theme: ThemeData(),
-        home: Material(
-          child: Builder(
-            builder: (BuildContext context) {
-              pageContext = context;
-              return Column(
-                children: <Widget>[
-                  const TextField(),
-                  TextField(focusNode: node),
-                ],
-              );
-            }
-          ),
-        ),
-      );
-
-      await tester.pumpWidget(widget);
-      expect(node.hasFocus, false);
-
-      node.requestFocus();
-      await tester.pumpAndSettle();
-      expect(node.hasFocus, true);
-
-      showDialog<void>(
-        context: pageContext,
-        builder: (BuildContext _) => const Center(),
-      );
-      await tester.pumpAndSettle();
-      expect(node.hasFocus, false);
-
-      Navigator.of(pageContext).pop();
-      await tester.pumpAndSettle();
-      expect(node.hasFocus, true);
-    });
-  });
 }
 
 class MockPageRoute extends Mock implements PageRoute<dynamic> { }