Adds getter/setter for slider semantics flag. (#65766)

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -3565,6 +3565,7 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
     bool? toggled,
     bool? selected,
     bool? button,
+    bool? slider,
     bool? link,
     bool? header,
     bool? textField,
@@ -3618,6 +3619,7 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
        _toggled = toggled,
        _selected = selected,
        _button = button,
+       _slider = slider,
        _link = link,
        _header = header,
        _textField = textField,
@@ -3764,6 +3766,17 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
     markNeedsSemanticsUpdate();
   }
 
+  /// If non-null, sets the [SemanticsConfiguration.isSlider] semantic to the
+  /// given value.
+  bool? get slider => _slider;
+  bool? _slider;
+  set slider(bool? value) {
+    if (slider == value)
+      return;
+    _slider = value;
+    markNeedsSemanticsUpdate();
+  }
+
   /// If non-null, sets the [SemanticsConfiguration.isLink] semantic to the
   /// given value.
   bool? get link => _link;
@@ -4477,6 +4490,8 @@ class RenderSemanticsAnnotations extends RenderProxyBox {
       config.isButton = button!;
     if (link != null)
       config.isLink = link!;
+    if (slider != null)
+      config.isSlider = slider!;
     if (header != null)
       config.isHeader = header!;
     if (textField != null)

packages/flutter/lib/src/semantics/semantics.dart

@@ -596,6 +596,7 @@ class SemanticsProperties extends DiagnosticableTree {
     this.link,
     this.header,
     this.textField,
+    this.slider,
     this.readOnly,
     this.focusable,
     this.focused,
@@ -694,6 +695,12 @@ class SemanticsProperties extends DiagnosticableTree {
   /// text field.
   final bool? textField;
 
+  /// If non-null, indicates that this subtree represents a slider.
+  ///
+  /// Talkback/\VoiceOver provides users with the hint "slider" when a
+  /// slider is focused.
+  final bool? slider;
+
   /// If non-null, indicates that this subtree is read only.
   ///
   /// Only applicable when [textField] is true.
@@ -3640,6 +3647,12 @@ class SemanticsConfiguration {
     _setFlag(SemanticsFlag.isHeader, value);
   }
 
+  /// Whether the owning [RenderObject] is a slider (true) or not (false).
+  bool get isSlider => _hasFlag(SemanticsFlag.isSlider);
+  set isSlider(bool value) {
+    _setFlag(SemanticsFlag.isSlider, value);
+  }
+
   /// Whether the owning [RenderObject] is considered hidden.
   ///
   /// Hidden elements are currently not visible on screen. They may be covered

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

@@ -6662,6 +6662,7 @@ class Semantics extends SingleChildRenderObjectWidget {
     bool? selected,
     bool? toggled,
     bool? button,
+    bool? slider,
     bool? link,
     bool? header,
     bool? textField,
@@ -6717,6 +6718,7 @@ class Semantics extends SingleChildRenderObjectWidget {
       toggled: toggled,
       selected: selected,
       button: button,
+      slider: slider,
       link: link,
       header: header,
       textField: textField,
@@ -6831,6 +6833,7 @@ class Semantics extends SingleChildRenderObjectWidget {
       toggled: properties.toggled,
       selected: properties.selected,
       button: properties.button,
+      slider: properties.slider,
       link: properties.link,
       header: properties.header,
       textField: properties.textField,
@@ -6902,6 +6905,7 @@ class Semantics extends SingleChildRenderObjectWidget {
       ..toggled = properties.toggled
       ..selected = properties.selected
       ..button = properties.button
+      ..slider = properties.slider
       ..link = properties.link
       ..header = properties.header
       ..textField = properties.textField

packages/flutter/test/widgets/custom_painter_test.dart

@@ -414,6 +414,7 @@ void _defineTests() {
             selected: true,
             hidden: true,
             button: true,
+            slider: true,
             link: true,
             textField: true,
             readOnly: true,
@@ -464,6 +465,7 @@ void _defineTests() {
             selected: true,
             hidden: true,
             button: true,
+            slider: true,
             link: true,
             textField: true,
             readOnly: true,

packages/flutter/test/widgets/semantics_test.dart

@@ -475,6 +475,7 @@ void main() {
           checked: true,
           selected: true,
           button: true,
+          slider: true,
           link: true,
           textField: true,
           readOnly: true,