Allow unknown device kind to scroll scrollables (#100800)

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

@@ -19,6 +19,9 @@ const Set<PointerDeviceKind> _kTouchLikeDeviceTypes = <PointerDeviceKind>{
   PointerDeviceKind.touch,
   PointerDeviceKind.stylus,
   PointerDeviceKind.invertedStylus,
+  // The VoiceAccess sends pointer events with unknown type when scrolling
+  // scrollables.
+  PointerDeviceKind.unknown,
 };
 
 /// The default overscroll indicator applied on [TargetPlatform.android].

packages/flutter/test/widgets/scroll_behavior_test.dart

@@ -134,6 +134,7 @@ void main() {
         PointerDeviceKind.touch,
         PointerDeviceKind.stylus,
         PointerDeviceKind.invertedStylus,
+        PointerDeviceKind.unknown,
       });
 
       // Use copyWith to modify drag devices

packages/flutter/test/widgets/scrollable_test.dart

@@ -1273,6 +1273,35 @@ void main() {
     expect(tester.takeException(), null);
   });
 
+  testWidgets('Accepts drag with unknown device kind by default', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/90912.
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: CustomScrollView(
+          slivers: <Widget>[
+            SliverToBoxAdapter(child: SizedBox(height: 2000.0)),
+          ],
+        ),
+      )
+    );
+    final TestGesture gesture = await tester.startGesture(tester.getCenter(find.byType(Scrollable), warnIfMissed: true), kind: ui.PointerDeviceKind.unknown);
+    expect(getScrollOffset(tester), 0.0);
+    await gesture.moveBy(const Offset(0.0, -200));
+    await tester.pump();
+    await tester.pumpAndSettle();
+
+    expect(getScrollOffset(tester), 200);
+
+    await gesture.moveBy(const Offset(0.0, 200));
+    await tester.pump();
+    await tester.pumpAndSettle();
+
+    expect(getScrollOffset(tester), 0.0);
+
+    await gesture.removePointer();
+    await tester.pump();
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS, TargetPlatform.macOS, TargetPlatform.android }));
+
   testWidgets('Does not scroll with mouse pointer drag when behavior is configured to ignore them', (WidgetTester tester) async {
     await pumpTest(tester, debugDefaultTargetPlatformOverride, enableMouseDrag: false);
     final TestGesture gesture = await tester.startGesture(tester.getCenter(find.byType(Scrollable), warnIfMissed: true), kind: ui.PointerDeviceKind.mouse);