[iOS] Fix Brush issue in Shapes after swipes in CarouselView (#13386)

* Added repro sample

* Fix the issue

Co-authored-by: Rui Marinho <me@ruimarinho.net>

Author: jsuarezruiz

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13376.xaml

@@ -0,0 +1,48 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<local:TestContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    xmlns:d="http://xamarin.com/schemas/2014/forms/design"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Title="Test 13376" xmlns:local="using:Xamarin.Forms.Controls"
+    x:Class="Xamarin.Forms.Controls.Issues.Issue13376">
+    <StackLayout>
+        <Label
+            Padding="12"
+            BackgroundColor="Black"
+            TextColor="White"
+            Text="Swipe and passes at least twice for each item, if the Ellipse is always rendered correctly the test has passed."/>
+        <CarouselView
+            ItemsSource="{Binding Items}">
+            <CarouselView.ItemTemplate>
+                <DataTemplate>
+                    <Grid RowDefinitions="*,*">
+                        <Ellipse  
+                            Stroke="Red"
+                            Fill="Yellow"
+                            VerticalOptions="Center"
+                            HeightRequest="200"
+                            HorizontalOptions="Center"
+                            WidthRequest="200"/>
+                        <Label
+                            x:Name="GreenLabel"
+                            Text="{Binding Text}"
+                            TextColor="DarkGreen"
+                            FontSize="Large"
+                            Grid.Row="0"
+                            VerticalOptions="Center"
+                            HorizontalOptions="Center"/>
+                        <Ellipse
+                            Fill="Gray" 
+                            Grid.Row="1"
+                            VerticalOptions="Center"
+                            HeightRequest="200"
+                            HorizontalOptions="Center"
+                            WidthRequest="200"/>
+                    </Grid>
+                </DataTemplate>
+            </CarouselView.ItemTemplate>
+        </CarouselView>
+    </StackLayout>
+</local:TestContentPage>

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Issue13376.xaml.cs

@@ -0,0 +1,61 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using Xamarin.Forms.CustomAttributes;
+using Xamarin.Forms.Internals;
+
+#if UITEST
+using Xamarin.UITest;
+using NUnit.Framework;
+using Xamarin.Forms.Core.UITests;
+#endif
+
+namespace Xamarin.Forms.Controls.Issues
+{
+    [Preserve(AllMembers = true)]
+    [Issue(IssueTracker.Github, 13376,
+		"[Bug] [iOS] Brush color lost on swiping",
+		PlatformAffected.iOS)]
+	public partial class Issue13376 : TestContentPage
+	{
+		public Issue13376()
+		{
+#if APP
+			InitializeComponent();
+            BindingContext = new Issue13376ViewModel();
+#endif
+        }
+
+		protected override void Init()
+		{
+		}
+    }
+
+    [Preserve(AllMembers = true)]
+    public class Issue13376Model
+    {
+        public Issue13376Model(string text)
+        {
+            Text = text;
+        }
+
+        public string Text { get; }
+    }
+
+    [Preserve(AllMembers = true)]
+    public class Issue13376ViewModel
+    {
+        public Issue13376ViewModel()
+        {
+            Items = new List<Issue13376Model>
+            {
+                new Issue13376Model("Item 1"),
+                new Issue13376Model("Item 2"),
+                new Issue13376Model("Item 3"),
+                new Issue13376Model("Item 4"),
+                new Issue13376Model("Item 5"),
+            };
+        }
+
+        public List<Issue13376Model> Items { get; }
+    }
+}

Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Xamarin.Forms.Controls.Issues.Shared.projitems

@@ -1721,6 +1721,7 @@
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutBackground.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutContentOffest.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)ShellFlyoutContentWithZeroMargin.cs" />
+    <Compile Include="$(MSBuildThisFileDirectory)Issue13376.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)LabelFormattedTextHtmlPadding.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue13436.xaml.cs" />
     <Compile Include="$(MSBuildThisFileDirectory)Issue12259.cs" />
@@ -2122,6 +2123,9 @@
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13136.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue13376.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Include="$(MSBuildThisFileDirectory)Issue12521.xaml">
       <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
     </EmbeddedResource>

Xamarin.Forms.Platform.iOS/Shapes/ShapeRenderer.cs

@@ -42,6 +42,7 @@ protected override void OnElementChanged(ElementChangedEventArgs<TShape> args)
                 {
                     _height = Element.Height;
                     _width = Element.Width;
+
                     UpdateSize();
                 }
             }