chore: Adjust Popup fix for Skia and WASM

On these platforms, changing the real Parent to be other than the visual parent breaks the current pointer implementation. As a workaround, we just override the publicly-visible FE.Parent value, without actually changing Store.Parent.

src/Uno.UI/UI/Xaml/Controls/Popup/PopupPanel.cs

@@ -73,7 +73,7 @@ protected override Size MeasureOverride(Size availableSize)
 
 			if (this.Log().IsEnabled(LogLevel.Debug))
 			{
-				this.Log().LogDebug($"Measured PopupPanel #={GetHashCode()} ({(Popup.CustomLayouter == null?"":"**using custom layouter**")}) DC={Popup.DataContext} child={child} offset={Popup.HorizontalOffset},{Popup.VerticalOffset} availableSize={availableSize} measured={_lastMeasuredSize}");
+				this.Log().LogDebug($"Measured PopupPanel #={GetHashCode()} ({(Popup.CustomLayouter == null ? "" : "**using custom layouter**")}) DC={Popup.DataContext} child={child} offset={Popup.HorizontalOffset},{Popup.VerticalOffset} availableSize={availableSize} measured={_lastMeasuredSize}");
 			}
 
 			// Note that we return the availableSize and not the _lastMeasuredSize. This is because this
@@ -179,13 +179,13 @@ private protected override void OnLoaded()
 			base.OnLoaded();
 			// Set Parent to the Popup, to obtain the same behavior as UWP that the Popup (and therefore the rest of the main visual tree)
 			// is reachable by scaling the combined Parent/GetVisualParent() hierarchy.
-			this.SetParent(Popup);
+			this.SetLogicalParent(Popup);
 		}
 
 		private protected override void OnUnloaded()
 		{
 			base.OnUnloaded();
-			this.SetParent(null);
+			this.SetLogicalParent(null);
 		}
 	}
 }

src/Uno.UI/UI/Xaml/DependencyObjectExtensions.cs

@@ -108,7 +108,7 @@ internal static bool HasParent(this object dependencyObject, DependencyObject se
 			var parent = dependencyObject.GetParent();
 			while (parent != null)
 			{
-				if(ReferenceEquals(parent, searchedParent))
+				if (ReferenceEquals(parent, searchedParent))
 				{
 					return true;
 				}
@@ -127,6 +127,21 @@ internal static void SetParent(this object dependencyObject, object parent)
 			GetStore(dependencyObject).Parent = parent;
 		}
 
+		internal static void SetLogicalParent(this FrameworkElement element, DependencyObject logicalParent)
+		{
+#if UNO_HAS_MANAGED_POINTERS || __WASM__ // WASM has managed-esque pointers
+
+			// UWP distinguishes between the 'logical parent' (or inheritance parent) and the 'visual parent' of an element. Uno already
+			// recognises this distinction on some targets, but for targets using CoerceHitTestVisibility() for hit testing, the pointer
+			// implementation depends upon the logical parent (ie DepObjStore.Parent) being identical to the visual parent, because it
+			// piggybacks on the DP inheritance mechanism. Therefore we use LogicalParentOverride as a workaround to modify the publicly-visible
+			// FrameworkElement.Parent without affecting DP propagation.
+			element.LogicalParentOverride = logicalParent;
+#else
+			SetParent(element, logicalParent);
+#endif
+		}
+
 		/// <summary>
 		/// Creates a SetValue precedence scoped override. All calls to SetValue
 		/// on the specified instance will be set to the specified precedence.

src/Uno.UI/UI/Xaml/FrameworkElement.cs

@@ -135,7 +135,21 @@ Windows.UI.Xaml.ResourceDictionary Resources
 #if __ANDROID__
 		new
 #endif
-		DependencyObject Parent => ((IDependencyObjectStoreProvider)this).Store.Parent as DependencyObject;
+		DependencyObject Parent =>
+#if UNO_HAS_MANAGED_POINTERS || __WASM__
+			LogicalParentOverride ??
+#endif
+			((IDependencyObjectStoreProvider)this).Store.Parent as DependencyObject;
+
+
+#if UNO_HAS_MANAGED_POINTERS || __WASM__
+		/// <summary>
+		/// Allows to override the publicly-visible <see cref="Parent"/> without modifying DP propagation.
+		/// </summary>
+		internal DependencyObject LogicalParentOverride { get; set; }
+
+		internal UIElement VisualParent => ((IDependencyObjectStoreProvider)this).Store.Parent as UIElement;
+#endif
 
 		private bool _isParsing;
 		/// <summary>

src/Uno.UI/UI/Xaml/UIElementExtensions.cs

@@ -10,7 +10,7 @@ public static partial class UIElementExtensions
 		/// <summary>
 		/// Get the parent view in the visual tree.
 		/// </summary>
-		public static UIElement GetVisualTreeParent(this UIElement uiElement) => (uiElement as FrameworkElement)?.Parent as UIElement;
+		public static UIElement GetVisualTreeParent(this UIElement uiElement) => (uiElement as FrameworkElement)?.VisualParent;
 	}
 }
 #endif