Fix the size of renderer controls

Ooui.Forms/Extensions/ElementExtensions.cs

@@ -8,7 +8,7 @@ namespace Ooui.Forms.Extensions
         public static SizeRequest GetSizeRequest (this Ooui.Element self, double widthConstraint, double heightConstraint,
             double minimumWidth = -1, double minimumHeight = -1)
         {
-            Size s = self.Text.MeasureSize (self.Style);
+            var s = self.Text.MeasureSize (self.Style);
 
             var request = new Size (
                 double.IsPositiveInfinity (s.Width) ? double.PositiveInfinity : s.Width,

Ooui.Forms/IVisualElementRenderer.cs

@@ -16,5 +16,7 @@ namespace Ooui.Forms
 		void SetElementSize (Size size);
 
         SizeRequest GetDesiredSize (double widthConstraint, double heightConstraint);
+
+        void SetControlSize (Size size);
 	}
 }

Ooui.Forms/Renderers/ViewRenderer.cs

@@ -97,6 +97,17 @@ namespace Ooui.Forms.Renderers
 			this.AppendChild (uiview);
 		}
 
+        public override void SetControlSize (Size size)
+        {
+            if (Control != null) {
+                //Control.Style.Position = "absolute";
+                //Control.Style.Left = "0px";
+                //Control.Style.Top = "0px";
+                Control.Style.Width = size.Width + "px";
+                Control.Style.Height = size.Height + "px";
+            }
+        }
+
 		protected override void SendVisualElementInitialized (VisualElement element, Ooui.Element nativeView)
 		{
 			base.SendVisualElementInitialized (element, Control);

Ooui.Forms/VisualElementRenderer.cs

@@ -129,6 +129,10 @@ namespace Ooui.Forms
             Xamarin.Forms.Layout.LayoutChildIntoBoundingRegion (Element, new Rectangle (Element.X, Element.Y, size.Width, size.Height));
         }
 
+        public virtual void SetControlSize (Size size)
+        {
+        }
+
         protected virtual void OnElementPropertyChanged (object sender, PropertyChangedEventArgs e)
         {
             if (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName) {

Ooui.Forms/VisualElementTracker.cs

@@ -145,6 +145,7 @@ namespace Ooui.Forms
                 uiview.Style.Top = y + "px";
                 uiview.Style.Width = width + "px";
                 uiview.Style.Height = height + "px";
+                Renderer.SetControlSize (new Size (width, height));
             }
             else if (width <= 0 || height <= 0) {
                 return;