Xamarin.Forms CALayerInvalidGeometry Exception workaround

JMWebPage.cs

//
// Add this file to your iOS project 
//
using System;
using Xamarin.Forms;

namespace Common
{
    public class JMWebPage : Page
    {
        //
        // Static Fields
        //
        public static readonly BindableProperty SourceProperty;

        //
        // Properties
        //
        public WebViewSource Source
        { 
            get
            {
                return (WebViewSource)base.GetValue(JMWebPage.SourceProperty);
            }
            set
            {
                base.SetValue(JMWebPage.SourceProperty, value);
            }
        }

        static JMWebPage()
        {
            JMWebPage.SourceProperty = BindableProperty.Create("Source", typeof(WebViewSource), typeof(JMWebPage), null, BindingMode.OneWay, null, null, null, null);
        }
    }
}

JMWebPageRenderer.cs

//
// Add this file to your shared project
//
using MonoTouch.UIKit;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using Common;
using Common.iOS;
using MonoTouch.Foundation;

[assembly: ExportRenderer (typeof(JMWebPage), typeof(JMWebPageRenderer))]
namespace Common.iOS
{
    public class JMWebPageRenderer : PageRenderer
    {
        protected UIWebView uiWebView;

        public override void ViewDidLoad()
        {
            base.ViewDidLoad();
            this.Element.PropertyChanged += new PropertyChangedEventHandler(this.OnHandlePropertyChanged);

            uiWebView = new UIWebView();
            uiWebView.ScrollView.DecelerationRate = UIScrollView.DecelerationRateNormal;
            uiWebView.Frame = this.View.Bounds;

            this.Add(uiWebView);
        }

        private void OnHandlePropertyChanged(object sender, PropertyChangedEventArgs e)
        {
            if (e.PropertyName == JMWebPage.SourceProperty.PropertyName)
            {
                var source = ((JMWebPage)this.Element).Source;
                var urlSource = source as UrlWebViewSource;
                if (urlSource != null)
                {
                    var url = NSUrl.FromString(urlSource.Url);
                    var request = NSUrlRequest.FromUrl(url);
                    uiWebView.LoadRequest(request);
                }
                else
                {
                    var htmlSource = source as HtmlWebViewSource;
                    if (htmlSource != null)
                    {
                        NSUrl url = string.IsNullOrWhiteSpace(htmlSource.BaseUrl) ? null : new NSUrl(htmlSource.BaseUrl);
                        uiWebView.LoadHtmlString(htmlSource.Html, url);
                    }
                }
            }
        }
    }
}

UrlWebPage.cs

//
// Add this file to your shared project
// create a UrlWebPage with:
// var page = new UrlWebPage { Url = "http://google.com" };
//
using System;
using Xamarin.Forms;

namespace Common
{
    #if __IOS2__
    public class UrlWebPage : UrlWebPage_iOS { }
    #else
    public class UrlWebPage : UrlWebPageBase { }
    #endif

    public class UrlWebPageBase : ContentPage
    {
        private WebView webView;

        public string Url { get; set; }

        public UrlWebPageBase()
        {
            webView = new WebView();
            Content = new StackLayout {

                Children = { webView }
            };
        }

        protected override void OnAppearing()
        {
            base.OnAppearing();
            HeightRequest = this.Height;
            WidthRequest = this.Width;
            webView.Source = new UrlWebViewSource { Url = this.Url };
        }
    }

    public class UrlWebPage_iOS : JMWebPage
    {
        public string Url { get; set; }

        protected override void OnAppearing()
        {
            base.OnAppearing();
            this.Source = new UrlWebViewSource { Url = this.Url };
        }
    }
}