Change Viewbox.Stretch to a styled property

src/Avalonia.Controls/ApiCompatBaseline.txt

@@ -4,10 +4,11 @@ InterfacesShouldHaveSameMembers : Interface member 'public System.Boolean Avalon
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.IMenuItem.StaysOpenOnClick.set(System.Boolean)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.INativeMenuExporterEventsImplBridge.RaiseClosed()' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Controls.INativeMenuExporterEventsImplBridge.RaiseOpening()' is present in the implementation but not in the contract.
+MembersMustExist : Member 'public Avalonia.AvaloniaProperty<Avalonia.Media.Stretch> Avalonia.AvaloniaProperty<Avalonia.Media.Stretch> Avalonia.Controls.Viewbox.StretchProperty' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public void Avalonia.Controls.Embedding.Offscreen.OffscreenTopLevelImplBase.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
 MembersMustExist : Member 'public Avalonia.AvaloniaProperty Avalonia.AvaloniaProperty Avalonia.Controls.Notifications.NotificationCard.CloseOnClickProperty' does not exist in the implementation but it does exist in the contract.
 EnumValuesMustMatch : Enum value 'Avalonia.Platform.ExtendClientAreaChromeHints Avalonia.Platform.ExtendClientAreaChromeHints.Default' is (System.Int32)2 in the implementation but (System.Int32)1 in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.ICursorImpl)' is present in the implementation but not in the contract.
 InterfacesShouldHaveSameMembers : Interface member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' is present in the contract but not in the implementation.
 MembersMustExist : Member 'public void Avalonia.Platform.ITopLevelImpl.SetCursor(Avalonia.Platform.IPlatformHandle)' does not exist in the implementation but it does exist in the contract.
-Total Issues: 11
+Total Issues: 12

src/Avalonia.Controls/Viewbox.cs

@@ -11,9 +11,8 @@ namespace Avalonia.Controls
         /// <summary>
         /// Defines the <see cref="Stretch"/> property.
         /// </summary>
-        public static readonly AvaloniaProperty<Stretch> StretchProperty =
-            AvaloniaProperty.RegisterDirect<Viewbox, Stretch>(nameof(Stretch),
-                v => v.Stretch, (c, v) => c.Stretch = v, Stretch.Uniform);
+        public static readonly StyledProperty<Stretch> StretchProperty =
+            AvaloniaProperty.Register<Image, Stretch>(nameof(Stretch), Stretch.Uniform);
 
         /// <summary>
         /// Defines the <see cref="StretchDirection"/> property.
@@ -21,8 +20,6 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<StretchDirection> StretchDirectionProperty =
             AvaloniaProperty.Register<Viewbox, StretchDirection>(nameof(StretchDirection), StretchDirection.Both);
 
-        private Stretch _stretch = Stretch.Uniform;
-
         static Viewbox()
         {
             ClipToBoundsProperty.OverrideDefaultValue<Viewbox>(true);
@@ -35,8 +32,8 @@ namespace Avalonia.Controls
         /// </summary>
         public Stretch Stretch
         {
-            get => _stretch;
-            set => SetAndRaise(StretchProperty, ref _stretch, value);
+            get => GetValue(StretchProperty);
+            set => SetValue(StretchProperty, value);
         }
 
         /// <summary>