Set slider semantics flag for sliders (#68019)

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

@@ -548,6 +548,7 @@ class _RenderCupertinoSlider extends RenderConstrainedBox {
     super.describeSemanticsConfiguration(config);
 
     config.isSemanticBoundary = isInteractive;
+    config.isSlider = true;
     if (isInteractive) {
       config.textDirection = textDirection;
       config.onIncrease = _increaseAction;

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

@@ -1529,6 +1529,7 @@ class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMix
     final SemanticsConfiguration config = SemanticsConfiguration();
     config.isEnabled = isEnabled;
     config.textDirection = textDirection;
+    config.isSlider = true;
     if (isEnabled) {
       config.onIncrease = increaseAction;
       config.onDecrease = decreaseAction;

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

@@ -707,6 +707,7 @@ class _SliderState extends State<Slider> with TickerProviderStateMixin {
 
     return Semantics(
       container: true,
+      slider: true,
       child: FocusableActionDetector(
         actions: _actionMap,
         shortcuts: _shortcutMap,

packages/flutter/test/cupertino/slider_test.dart

@@ -318,6 +318,7 @@ void main() {
             increasedValue: '60%',
             decreasedValue: '40%',
             textDirection: TextDirection.ltr,
+            flags: <SemanticsFlag>[SemanticsFlag.isSlider],
             actions: SemanticsAction.decrease.index | SemanticsAction.increase.index,
           ),
         ],
@@ -341,7 +342,14 @@ void main() {
     );
 
     expect(semantics, hasSemantics(
-      TestSemantics.root(),
+      TestSemantics.root(
+        children: <TestSemantics>[
+          TestSemantics(
+            id: 1,
+            flags: <SemanticsFlag>[SemanticsFlag.isSlider],
+          )
+        ],
+      ),
       ignoreRect: true,
       ignoreTransform: true,
     ));
@@ -365,6 +373,7 @@ void main() {
     );
 
     expect(tester.getSemantics(find.byType(CupertinoSlider)), matchesSemantics(
+      isSlider: true,
       hasIncreaseAction: true,
       hasDecreaseAction: true,
       value: '50%',
@@ -387,6 +396,7 @@ void main() {
     );
 
     expect(tester.getSemantics(find.byType(CupertinoSlider)), matchesSemantics(
+      isSlider: true,
       hasIncreaseAction: true,
       hasDecreaseAction: true,
       value: '60%',

packages/flutter/test/material/range_slider_test.dart

@@ -1775,6 +1775,7 @@ void main() {
             children:  <Matcher>[
               matchesSemantics(
                 isEnabled: true,
+                isSlider: true,
                 hasEnabledState: true,
                 hasIncreaseAction: true,
                 hasDecreaseAction: true,
@@ -1784,6 +1785,7 @@ void main() {
               ),
               matchesSemantics(
                 isEnabled: true,
+                isSlider: true,
                 hasEnabledState: true,
                 hasIncreaseAction: true,
                 hasDecreaseAction: true,

packages/flutter/test/material/slider_test.dart

@@ -1345,7 +1345,7 @@ void main() {
                       children: <TestSemantics>[
                         TestSemantics(
                           id: 4,
-                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable],
+                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable, SemanticsFlag.isSlider],
                           actions: <SemanticsAction>[SemanticsAction.increase, SemanticsAction.decrease],
                           value: '50%',
                           increasedValue: '55%',
@@ -1403,6 +1403,7 @@ void main() {
                             SemanticsFlag.hasEnabledState,
                             // isFocusable is delayed by 1 frame.
                             SemanticsFlag.isFocusable,
+                            SemanticsFlag.isSlider,
                           ],
                           value: '50%',
                           increasedValue: '55%',
@@ -1443,6 +1444,7 @@ void main() {
                           id: 4,
                           flags: <SemanticsFlag>[
                             SemanticsFlag.hasEnabledState,
+                            SemanticsFlag.isSlider,
                           ],
                           value: '50%',
                           increasedValue: '55%',
@@ -1508,7 +1510,7 @@ void main() {
                       children: <TestSemantics>[
                         TestSemantics(
                           id: 4,
-                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable],
+                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable, SemanticsFlag.isSlider],
                           actions: <SemanticsAction>[SemanticsAction.increase, SemanticsAction.decrease],
                           value: '50%',
                           increasedValue: '60%',
@@ -1562,7 +1564,7 @@ void main() {
                       children: <TestSemantics>[
                         TestSemantics(
                           id: 5,
-                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState],
+                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isSlider],
                           value: '50%',
                           increasedValue: '60%',
                           decreasedValue: '40%',
@@ -1623,7 +1625,7 @@ void main() {
                       children: <TestSemantics>[
                         TestSemantics(
                           id: 4,
-                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable],
+                          flags: <SemanticsFlag>[SemanticsFlag.hasEnabledState, SemanticsFlag.isEnabled, SemanticsFlag.isFocusable, SemanticsFlag.isSlider],
                           actions: <SemanticsAction>[SemanticsAction.increase, SemanticsAction.decrease],
                           value: '40',
                           increasedValue: '60',

packages/flutter_test/lib/src/matchers.dart

@@ -468,6 +468,7 @@ Matcher matchesSemantics({
   bool hasToggledState = false,
   bool isToggled = false,
   bool hasImplicitScrolling = false,
+  bool isSlider = false,
   // Actions //
   bool hasTapAction = false,
   bool hasLongPressAction = false,
@@ -519,6 +520,7 @@ Matcher matchesSemantics({
     if (hasToggledState) SemanticsFlag.hasToggledState,
     if (isToggled) SemanticsFlag.isToggled,
     if (hasImplicitScrolling) SemanticsFlag.hasImplicitScrolling,
+    if (isSlider) SemanticsFlag.isSlider
   ];
 
   final List<SemanticsAction> actions = <SemanticsAction>[