Generate onSlidingComplete callbacks when sliders adjusted via 111y.

When sliders are adjusted via accessibility, no onSlidingComplete callback is
generated. This causes problems for components which perform behavior in this
callback, and means that such components don't behave properly when adjusted via
accessibility.

Ensure that sliders call the onSlidingComplete callback after adjusted via
accessibility.

React/Views/RCTSlider.m

@@ -84,4 +84,24 @@ - (UIImage *)thumbImage
   return [self thumbImageForState:UIControlStateNormal];
 }
 
+- (void)accessibilityIncrement
+{
+  [super accessibilityIncrement];
+  if (_onSlidingComplete) {
+    _onSlidingComplete(@{
+        @"value": @(self.value),
+    });
+  }
+}
+
+- (void)accessibilityDecrement
+{
+  [super accessibilityDecrement];
+  if (_onSlidingComplete) {
+    _onSlidingComplete(@{
+        @"value": @(self.value),
+    });
+  }
+}
+
 @end

ReactAndroid/src/main/java/com/facebook/react/views/slider/ReactSliderManager.java

@@ -10,10 +10,14 @@
 import android.graphics.PorterDuff;
 import android.graphics.drawable.Drawable;
 import android.graphics.drawable.LayerDrawable;
+import android.os.Bundle;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.SeekBar;
 import androidx.annotation.Nullable;
+import androidx.core.view.accessibility.AccessibilityNodeInfoCompat.AccessibilityActionCompat;
+import androidx.core.view.AccessibilityDelegateCompat;
+import androidx.core.view.ViewCompat;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.common.MapBuilder;
@@ -132,7 +136,9 @@ public Class getShadowNodeClass() {
 
   @Override
   protected ReactSlider createViewInstance(ThemedReactContext context) {
-    return new ReactSlider(context, null, STYLE);
+    final ReactSlider slider = new ReactSlider(context, null, STYLE);
+    ViewCompat.setAccessibilityDelegate(slider, sAccessibilityDelegate);
+    return slider;
   }
 
   @Override
@@ -256,4 +262,25 @@ public long measure(
   protected ViewManagerDelegate<ReactSlider> getDelegate() {
     return mDelegate;
   }
+
+  protected static class ReactSliderAccessibilityDelegate extends AccessibilityDelegateCompat {
+    private static boolean isSliderAction(int action) {
+      return (action == AccessibilityActionCompat.ACTION_SCROLL_FORWARD.getId()) ||
+        (action == AccessibilityActionCompat.ACTION_SCROLL_BACKWARD.getId()) ||
+        (action == AccessibilityActionCompat.ACTION_SET_PROGRESS.getId());
+    }
+
+    @Override
+    public boolean performAccessibilityAction(View host, int action, Bundle args) {
+      if (isSliderAction(action)) {
+        ON_CHANGE_LISTENER.onStartTrackingTouch((SeekBar)host);        
+      }
+      final boolean rv = super.performAccessibilityAction(host, action, args);
+      if (isSliderAction(action)) {
+        ON_CHANGE_LISTENER.onStopTrackingTouch((SeekBar)host);        
+      }
+      return rv;
+    }
+  };
+  protected static ReactSliderAccessibilityDelegate sAccessibilityDelegate = new ReactSliderAccessibilityDelegate();
 }