Remove TreeItemContainerGenerator

src/Avalonia.Controls/Generators/TreeItemContainerGenerator.cs

@@ -1,10 +0,0 @@
-namespace Avalonia.Controls.Generators
-{
-    public class TreeItemContainerGenerator : ItemContainerGenerator
-    {
-        internal TreeItemContainerGenerator(TreeView owner)
-            : base(owner)
-        {
-        }
-    }
-}

src/Avalonia.Controls/ItemsControl.cs

@@ -101,11 +101,7 @@ namespace Avalonia.Controls
         /// Gets the <see cref="ItemContainerGenerator"/> for the control.
         /// </summary>
         public ItemContainerGenerator ItemContainerGenerator
-        {
-#pragma warning disable CS0612 // Type or member is obsolete
-            get => _itemContainerGenerator ??= CreateItemContainerGenerator();
-#pragma warning restore CS0612 // Type or member is obsolete
-        }
+            => _itemContainerGenerator ??= new ItemContainerGenerator(this);
 
         /// <summary>
         /// Gets the items to display.
@@ -659,20 +655,6 @@ namespace Avalonia.Controls
             ItemCount = ItemsView.Count;
         }
 
-        /// <summary>
-        /// Creates the <see cref="ItemContainerGenerator"/>
-        /// </summary>
-        /// <remarks>
-        /// This method is only present for backwards compatibility with 0.10.x in order for
-        /// TreeView to be able to create a <see cref="TreeItemContainerGenerator"/>. Can be
-        /// removed in 12.0.
-        /// </remarks>
-        [Obsolete, EditorBrowsable(EditorBrowsableState.Never)]
-        private protected virtual ItemContainerGenerator CreateItemContainerGenerator()
-        {
-            return new ItemContainerGenerator(this);
-        }
-
         internal void AddLogicalChild(Control c)
         {
             if (!LogicalChildren.Contains(c))

src/Avalonia.Controls/TreeView.cs

@@ -76,12 +76,6 @@ namespace Avalonia.Controls
             remove => RemoveHandler(SelectingItemsControl.SelectionChangedEvent, value);
         }
 
-        /// <summary>
-        /// Gets the <see cref="TreeItemContainerGenerator"/> for the tree view.
-        /// </summary>
-        public new TreeItemContainerGenerator ItemContainerGenerator =>
-            (TreeItemContainerGenerator)base.ItemContainerGenerator;
-
         /// <summary>
         /// Gets or sets a value indicating whether to automatically scroll to newly selected items.
         /// </summary>
@@ -773,12 +767,6 @@ namespace Avalonia.Controls
             }
         }
 
-        [Obsolete, EditorBrowsable(EditorBrowsableState.Never)]
-        private protected override ItemContainerGenerator CreateItemContainerGenerator()
-        {
-            return new TreeItemContainerGenerator(this);
-        }
-
         /// <summary>
         /// Find which node is first in hierarchy.
         /// </summary>