Revert "Improve the ScrollBar behavior when nested (#71843)" (#74088)

This reverts commit 99daddc2.

packages/flutter/lib/src/cupertino/scrollbar.dart

@@ -61,7 +61,6 @@ class CupertinoScrollbar extends RawScrollbar {
     this.thicknessWhileDragging = defaultThicknessWhileDragging,
     Radius radius = defaultRadius,
     this.radiusWhileDragging = defaultRadiusWhileDragging,
-    ScrollNotificationPredicate? notificationPredicate,
   }) : assert(thickness != null),
        assert(thickness < double.infinity),
        assert(thicknessWhileDragging != null),
@@ -78,7 +77,6 @@ class CupertinoScrollbar extends RawScrollbar {
          fadeDuration: _kScrollbarFadeDuration,
          timeToFade: _kScrollbarTimeToFade,
          pressDuration: const Duration(milliseconds: 100),
-         notificationPredicate: notificationPredicate ?? defaultScrollNotificationPredicate,
        );
 
   /// Default value for [thickness] if it's not specified in [CupertinoScrollbar].

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

@@ -153,7 +153,6 @@ class _MaterialScrollbar extends RawScrollbar {
     this.hoverThickness,
     double? thickness,
     Radius? radius,
-    ScrollNotificationPredicate? notificationPredicate,
   }) : super(
          key: key,
          child: child,
@@ -164,7 +163,6 @@ class _MaterialScrollbar extends RawScrollbar {
          fadeDuration: _kScrollbarFadeDuration,
          timeToFade: _kScrollbarTimeToFade,
          pressDuration: Duration.zero,
-         notificationPredicate: notificationPredicate ?? defaultScrollNotificationPredicate,
        );
 
   final bool? showTrackOnHover;

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

@@ -565,10 +565,6 @@ class ScrollbarPainter extends ChangeNotifier implements CustomPainter {
 /// visible without the fade animation. This requires that a [ScrollController]
 /// is provided to [controller], or that the [PrimaryScrollController] is available.
 ///
-/// If the scrollbar is wrapped around multiple [ScrollView]s, it only responds to
-/// the nearest scrollView and shows the corresponding scrollbar thumb by default.
-/// Set [notificationPredicate] to something else for more complicated behaviors.
-///
 /// Scrollbars are interactive and will also use the [PrimaryScrollController] if
 /// a [controller] is not set. Scrollbar thumbs can be dragged along the main axis
 /// of the [ScrollView] to change the [ScrollPosition]. Tapping along the track
@@ -611,7 +607,6 @@ class RawScrollbar extends StatefulWidget {
     this.fadeDuration = _kScrollbarFadeDuration,
     this.timeToFade = _kScrollbarTimeToFade,
     this.pressDuration = Duration.zero,
-    this.notificationPredicate = defaultScrollNotificationPredicate,
   }) : assert(child != null),
        assert(fadeDuration != null),
        assert(timeToFade != null),
@@ -772,14 +767,6 @@ class RawScrollbar extends StatefulWidget {
   /// Cannot be null, defaults to [Duration.zero].
   final Duration pressDuration;
 
-  /// A check that specifies whether a [ScrollNotification] should be
-  /// handled by this widget.
-  ///
-  /// By default, checks whether `notification.depth == 0`. That means if the
-  /// scrollbar is wrapped around multiple [ScrollView]s, it only responds to the
-  /// nearest scrollView and shows the corresponding scrollbar thumb.
-  final ScrollNotificationPredicate notificationPredicate;
-
   @override
   RawScrollbarState<RawScrollbar> createState() => RawScrollbarState<RawScrollbar>();
 }
@@ -1044,8 +1031,6 @@ class RawScrollbarState<T extends RawScrollbar> extends State<T> with TickerProv
   }
 
   bool _handleScrollNotification(ScrollNotification notification) {
-    if (!widget.notificationPredicate(notification))
-      return false;
 
     final ScrollMetrics metrics = notification.metrics;
     if (metrics.maxScrollExtent <= metrics.minScrollExtent)

packages/flutter/test/widgets/scrollbar_test.dart

@@ -804,67 +804,4 @@ void main() {
         ),
     );
   });
-
-  // Regression test for https://github.com/flutter/flutter/issues/66444
-  testWidgets("Scrollbar doesn't show when scroll the inner scrollable widget", (WidgetTester tester) async {
-    final GlobalKey key1 = GlobalKey();
-    final GlobalKey key2 = GlobalKey();
-    final GlobalKey outerKey = GlobalKey();
-    final GlobalKey innerKey = GlobalKey();
-    await tester.pumpWidget(
-      Directionality(
-        textDirection: TextDirection.ltr,
-        child: MediaQuery(
-          data: const MediaQueryData(),
-          child: RawScrollbar(
-            key: key2,
-            thumbColor: const Color(0x11111111),
-            child: SingleChildScrollView(
-              key: outerKey,
-              child: SizedBox(
-                height: 1000.0,
-                width: double.infinity,
-                child: Column(
-                  children: <Widget>[
-                    RawScrollbar(
-                      key: key1,
-                      thumbColor: const Color(0x22222222),
-                      child: SizedBox(
-                        height: 300.0,
-                        width: double.infinity,
-                        child: SingleChildScrollView(
-                          key: innerKey,
-                          child: const SizedBox(
-                            key: Key('Inner scrollable'),
-                            height: 1000.0,
-                            width: double.infinity,
-                          ),
-                        ),
-                      ),
-                    ),
-                  ],
-                ),
-              ),
-            ),
-          ),
-        ),
-      ),
-    );
-
-    // Drag the inner scrollable widget.
-    await tester.drag(find.byKey(innerKey), const Offset(0.0, -25.0));
-    await tester.pump();
-    // Scrollbar fully showing.
-    await tester.pump(const Duration(milliseconds: 500));
-
-    expect(
-      tester.renderObject(find.byKey(key2)),
-      paintsExactlyCountTimes(#drawRect, 2), // Each bar will call [drawRect] twice.
-    );
-
-    expect(
-      tester.renderObject(find.byKey(key1)),
-      paintsExactlyCountTimes(#drawRect, 2),
-    );
-  });
 }