Move ChildrenChanged to AutomationPeer.

src/Avalonia.Controls/Automation/Peers/AutomationPeer.cs

@@ -167,8 +167,21 @@ namespace Avalonia.Automation.Peers
         /// <returns>The provider, or null if not implemented on this peer.</returns>
         public T? GetProvider<T>() => (T?)GetProviderCore(typeof(T));
 
+        /// <summary>
+        /// Occurs when the children of the automation peer have changed.
+        /// </summary>
+        public event EventHandler? ChildrenChanged;
+
+        /// <summary>
+        /// Occurs when a property value of the automation peer has changed.
+        /// </summary>
         public event EventHandler<AutomationPropertyChangedEventArgs>? PropertyChanged;
 
+        /// <summary>
+        /// Raises an event to notify the automation client the the children of the peer have changed.
+        /// </summary>
+        protected void RaiseChildrenChangedEvent() => ChildrenChanged?.Invoke(this, EventArgs.Empty);
+
         /// <summary>
         /// Raises an event to notify the automation client of a changed property value.
         /// </summary>

src/Avalonia.Controls/Automation/Peers/ControlAutomationPeer.cs

@@ -26,8 +26,6 @@ namespace Avalonia.Automation.Peers
 
         public Control Owner { get; }
 
-        public event EventHandler? ChildrenChanged;
-
         public AutomationPeer GetOrCreate(Control element)
         {
             if (element == Owner)
@@ -110,7 +108,7 @@ namespace Avalonia.Automation.Peers
         protected void InvalidateChildren()
         {
             _childrenValid = false;
-            ChildrenChanged?.Invoke(this, EventArgs.Empty);
+            RaiseChildrenChangedEvent();
         }
 
         /// <summary>