Prep VisualElement (and descendants) for removal of InternalsVisibleTo (#141)

31 files changed, 384 insertions, 59 deletions

diff --git a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla37462.cs b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla37462.cs
index 6e3c3aab..89c3b032 100644
--- a/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla37462.cs
+++ b/Xamarin.Forms.Controls.Issues/Xamarin.Forms.Controls.Issues.Shared/Bugzilla37462.cs
@@ -22,7 +22,7 @@ namespace Xamarin.Forms.Controls
 			var label1 = new Label { Text = "This is a label on page 1" };
 			page1.Content = new StackLayout { Children = { button1, label1 } };
 			page1.Appearing += (sender, args) => {
-				page1.InvalidateMeasure (InvalidationTrigger.MeasureChanged);
+				((IVisualElementController)page1).InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 			};
 
 			var page2 = new ContentPage { Title = "Page 2" };
diff --git a/Xamarin.Forms.Core.UnitTests/GridTests.cs b/Xamarin.Forms.Core.UnitTests/GridTests.cs
index 203d3b64..359d2b5b 100644
--- a/Xamarin.Forms.Core.UnitTests/GridTests.cs
+++ b/Xamarin.Forms.Core.UnitTests/GridTests.cs
@@ -2,6 +2,7 @@ using NUnit.Framework;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms.Core.UnitTests
 {
@@ -1555,7 +1556,7 @@ namespace Xamarin.Forms.Core.UnitTests
 			bool fire = true;
 			child.SizeChanged += (sender, args) => {
 				if (fire)
-					child.InvalidateMeasure (InvalidationTrigger.Undefined);
+					((IVisualElementController)child).InvalidateMeasure(InvalidationTrigger.Undefined);
 				fire = false;
 			};
 
diff --git a/Xamarin.Forms.Core/AbsoluteLayout.cs b/Xamarin.Forms.Core/AbsoluteLayout.cs
index 51b5ca12..aceec2b3 100644
--- a/Xamarin.Forms.Core/AbsoluteLayout.cs
+++ b/Xamarin.Forms.Core/AbsoluteLayout.cs
@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
@@ -132,7 +133,7 @@ namespace Xamarin.Forms
 		{
 			if (e.PropertyName == LayoutFlagsProperty.PropertyName || e.PropertyName == LayoutBoundsProperty.PropertyName)
 			{
-				InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 				UpdateChildrenLayout();
 			}
 		}
diff --git a/Xamarin.Forms.Core/Button.cs b/Xamarin.Forms.Core/Button.cs
index 9c746c9e..72f98814 100644
--- a/Xamarin.Forms.Core/Button.cs
+++ b/Xamarin.Forms.Core/Button.cs
@@ -2,6 +2,7 @@ using System;
 using System.Diagnostics;
 using System.Globalization;
 using System.Windows.Input;
+using Xamarin.Forms.Internals;
 using Xamarin.Forms.Platform;
 
 namespace Xamarin.Forms
@@ -18,7 +19,7 @@ namespace Xamarin.Forms
 			BindableProperty.Create("ContentLayout", typeof(ButtonContentLayout), typeof(Button), new ButtonContentLayout(ButtonContentLayout.ImagePosition.Left, DefaultSpacing));
 
 		public static readonly BindableProperty TextProperty = BindableProperty.Create("Text", typeof(string), typeof(Button), null,
-			propertyChanged: (bindable, oldVal, newVal) => ((Button)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged));
+			propertyChanged: (bindable, oldVal, newVal) => ((Button)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged));
 
 		public static readonly BindableProperty TextColorProperty = BindableProperty.Create("TextColor", typeof(Color), typeof(Button), Color.Default);
 
@@ -178,7 +179,7 @@ namespace Xamarin.Forms
 			if (button._cancelEvents)
 				return;
 
-			button.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			button.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 
 			button._cancelEvents = true;
 
@@ -219,7 +220,7 @@ namespace Xamarin.Forms
 		void OnSourceChanged(object sender, EventArgs eventArgs)
 		{
 			OnPropertyChanged(ImageProperty.PropertyName);
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		void OnSourcePropertyChanged(ImageSource oldvalue, ImageSource newvalue)
@@ -229,7 +230,7 @@ namespace Xamarin.Forms
 				newvalue.SourceChanged += OnSourceChanged;
 				SetInheritedBindingContext(newvalue, BindingContext);
 			}
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		void OnSourcePropertyChanging(ImageSource oldvalue, ImageSource newvalue)
@@ -245,7 +246,7 @@ namespace Xamarin.Forms
 			if (button._cancelEvents)
 				return;
 
-			button.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			button.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 
 			button._cancelEvents = true;
 
diff --git a/Xamarin.Forms.Core/Grid.cs b/Xamarin.Forms.Core/Grid.cs
index 442146c2..a0460af5 100644
--- a/Xamarin.Forms.Core/Grid.cs
+++ b/Xamarin.Forms.Core/Grid.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.ComponentModel;
 using System.Linq;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
@@ -17,10 +18,10 @@ namespace Xamarin.Forms
 		public static readonly BindableProperty ColumnSpanProperty = BindableProperty.CreateAttached("ColumnSpan", typeof(int), typeof(Grid), 1, validateValue: (bindable, value) => (int)value >= 1);
 
 		public static readonly BindableProperty RowSpacingProperty = BindableProperty.Create("RowSpacing", typeof(double), typeof(Grid), 6d,
-			propertyChanged: (bindable, oldValue, newValue) => ((Grid)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged));
+			propertyChanged: (bindable, oldValue, newValue) => ((Grid)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged));
 
 		public static readonly BindableProperty ColumnSpacingProperty = BindableProperty.Create("ColumnSpacing", typeof(double), typeof(Grid), 6d,
-			propertyChanged: (bindable, oldValue, newValue) => ((Grid)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged));
+			propertyChanged: (bindable, oldValue, newValue) => ((Grid)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged));
 
 		public static readonly BindableProperty ColumnDefinitionsProperty = BindableProperty.Create("ColumnDefinitions", typeof(ColumnDefinitionCollection), typeof(Grid), null,
 			validateValue: (bindable, value) => value != null, propertyChanged: (bindable, oldvalue, newvalue) =>
@@ -211,9 +212,9 @@ namespace Xamarin.Forms
 			view.ComputedConstraint = result;
 		}
 
-		internal override void InvalidateMeasure(InvalidationTrigger trigger)
+		internal override void InvalidateMeasureInternal(InvalidationTrigger trigger)
 		{
-			base.InvalidateMeasure(trigger);
+			base.InvalidateMeasureInternal(trigger);
 			_columns = null;
 			_rows = null;
 		}
diff --git a/Xamarin.Forms.Core/IVisualElementController.cs b/Xamarin.Forms.Core/IVisualElementController.cs
index 03be293a..672f47de 100644
--- a/Xamarin.Forms.Core/IVisualElementController.cs
+++ b/Xamarin.Forms.Core/IVisualElementController.cs
@@ -1,7 +1,10 @@
+using Xamarin.Forms.Internals;
+
 namespace Xamarin.Forms
 {
 	public interface IVisualElementController : IElementController
 	{
 		void NativeSizeChanged();
+		void InvalidateMeasure(InvalidationTrigger trigger);
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Core/Image.cs b/Xamarin.Forms.Core/Image.cs
index 4528f3b9..7d6299ac 100644
--- a/Xamarin.Forms.Core/Image.cs
+++ b/Xamarin.Forms.Core/Image.cs
@@ -1,4 +1,5 @@
 using System;
+using Xamarin.Forms.Internals;
 using Xamarin.Forms.Platform;
 
 namespace Xamarin.Forms
@@ -110,7 +111,7 @@ namespace Xamarin.Forms
 		void OnSourceChanged(object sender, EventArgs eventArgs)
 		{
 			OnPropertyChanged(SourceProperty.PropertyName);
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		static void OnSourcePropertyChanged(BindableObject bindable, object oldvalue, object newvalue)
@@ -125,7 +126,7 @@ namespace Xamarin.Forms
 				newvalue.SourceChanged += OnSourceChanged;
 				SetInheritedBindingContext(newvalue, BindingContext);
 			}
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		static void OnSourcePropertyChanging(BindableObject bindable, object oldvalue, object newvalue)
diff --git a/Xamarin.Forms.Core/InvalidationTrigger.cs b/Xamarin.Forms.Core/Internals/InvalidationTrigger.cs
index e7db534e..9a4180e4 100644
--- a/Xamarin.Forms.Core/InvalidationTrigger.cs
+++ b/Xamarin.Forms.Core/Internals/InvalidationTrigger.cs
@@ -1,9 +1,9 @@
 using System;
 
-namespace Xamarin.Forms
+namespace Xamarin.Forms.Internals
 {
 	[Flags]
-	internal enum InvalidationTrigger
+	public enum InvalidationTrigger
 	{
 		Undefined = 0,
 		MeasureChanged = 1 << 0,
diff --git a/Xamarin.Forms.Core/InvalidationEventArgs.cs b/Xamarin.Forms.Core/InvalidationEventArgs.cs
index d88e2519..1dd5c098 100644
--- a/Xamarin.Forms.Core/InvalidationEventArgs.cs
+++ b/Xamarin.Forms.Core/InvalidationEventArgs.cs
@@ -1,4 +1,5 @@
 using System;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
diff --git a/Xamarin.Forms.Core/Label.cs b/Xamarin.Forms.Core/Label.cs
index 1efbd668..1385b763 100644
--- a/Xamarin.Forms.Core/Label.cs
+++ b/Xamarin.Forms.Core/Label.cs
@@ -1,5 +1,6 @@
 using System;
 using System.ComponentModel;
+using Xamarin.Forms.Internals;
 using Xamarin.Forms.Platform;
 
 namespace Xamarin.Forms
@@ -41,13 +42,13 @@ namespace Xamarin.Forms
 			{
 				if (newvalue != null)
 					((FormattedString)newvalue).PropertyChanged += ((Label)bindable).OnFormattedTextChanged;
-				((Label)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				((Label)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 				if (newvalue != null)
 					((Label)bindable).Text = null;
 			});
 
 		public static readonly BindableProperty LineBreakModeProperty = BindableProperty.Create("LineBreakMode", typeof(LineBreakMode), typeof(Label), LineBreakMode.WordWrap,
-			propertyChanged: (bindable, oldvalue, newvalue) => ((Label)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged));
+			propertyChanged: (bindable, oldvalue, newvalue) => ((Label)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged));
 
 		bool _cancelEvents;
 
@@ -158,7 +159,7 @@ namespace Xamarin.Forms
 
 			label._cancelEvents = false;
 
-			label.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		static void OnFontAttributesChanged(BindableObject bindable, object oldValue, object newValue)
@@ -189,7 +190,7 @@ namespace Xamarin.Forms
 
 			label._cancelEvents = false;
 
-			label.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		static void OnFontFamilyChanged(BindableObject bindable, object oldValue, object newValue)
@@ -217,7 +218,7 @@ namespace Xamarin.Forms
 			}
 
 			label._cancelEvents = false;
-			label.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		static void OnFontSizeChanged(BindableObject bindable, object oldValue, object newValue)
@@ -247,7 +248,7 @@ namespace Xamarin.Forms
 
 			label._cancelEvents = false;
 
-			label.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			label.InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		void OnFormattedTextChanged(object sender, PropertyChangedEventArgs e)
@@ -270,7 +271,7 @@ namespace Xamarin.Forms
 			bool isVerticallyFixed = (label.Constraint & LayoutConstraint.VerticallyFixed) != 0;
 			bool isSingleLine = !(breakMode == LineBreakMode.CharacterWrap || breakMode == LineBreakMode.WordWrap);
 			if (!isVerticallyFixed || !isSingleLine)
-				((Label)bindable).InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				((Label)bindable).InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 			if (newvalue != null)
 				((Label)bindable).FormattedText = null;
 		}
diff --git a/Xamarin.Forms.Core/Layout.cs b/Xamarin.Forms.Core/Layout.cs
index a7864070..a98e46a1 100644
--- a/Xamarin.Forms.Core/Layout.cs
+++ b/Xamarin.Forms.Core/Layout.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Linq;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
@@ -168,7 +169,7 @@ namespace Xamarin.Forms
 		protected virtual void InvalidateLayout()
 		{
 			_hasDoneLayout = false;
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 			if (!_hasDoneLayout)
 				ForceLayout();
 		}
@@ -304,11 +305,11 @@ namespace Xamarin.Forms
 			_allocatedFlag = false;
 			if (trigger == InvalidationTrigger.RendererReady)
 			{
-				InvalidateMeasure(InvalidationTrigger.RendererReady);
+				InvalidateMeasureInternal(InvalidationTrigger.RendererReady);
 			}
 			else
 			{
-				InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 			}
 
 			s_resolutionList.Add(new KeyValuePair<Layout, int>(this, GetElementDepth(this)));
diff --git a/Xamarin.Forms.Core/Page.cs b/Xamarin.Forms.Core/Page.cs
index 903f4b53..2e1caf0f 100644
--- a/Xamarin.Forms.Core/Page.cs
+++ b/Xamarin.Forms.Core/Page.cs
@@ -5,6 +5,7 @@ using System.Collections.Specialized;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+using Xamarin.Forms.Internals;
 using Xamarin.Forms.Platform;
 
 namespace Xamarin.Forms
@@ -283,7 +284,7 @@ namespace Xamarin.Forms
 			}
 
 			_allocatedFlag = false;
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 			if (!_allocatedFlag && Width >= 0 && Height >= 0)
 			{
 				SizeAllocated(Width, Height);
@@ -348,7 +349,7 @@ namespace Xamarin.Forms
 			view.MeasureInvalidated += OnChildMeasureInvalidated;
 
 			OnChildAdded(view);
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		void OnInternalRemoved(VisualElement view)
diff --git a/Xamarin.Forms.Core/StackLayout.cs b/Xamarin.Forms.Core/StackLayout.cs
index 4dc7bfa3..e115a23d 100644
--- a/Xamarin.Forms.Core/StackLayout.cs
+++ b/Xamarin.Forms.Core/StackLayout.cs
@@ -1,4 +1,5 @@
 using System;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
@@ -73,10 +74,10 @@ namespace Xamarin.Forms
 			ComputeConstraintForView(view, false);
 		}
 
-		internal override void InvalidateMeasure(InvalidationTrigger trigger)
+		internal override void InvalidateMeasureInternal(InvalidationTrigger trigger)
 		{
 			_layoutInformation = new LayoutInformation();
-			base.InvalidateMeasure(trigger);
+			base.InvalidateMeasureInternal(trigger);
 		}
 
 		void AlignOffAxis(LayoutInformation layout, StackOrientation orientation, double widthConstraint, double heightConstraint)
diff --git a/Xamarin.Forms.Core/View.cs b/Xamarin.Forms.Core/View.cs
index d03c74bb..1ff51d9c 100644
--- a/Xamarin.Forms.Core/View.cs
+++ b/Xamarin.Forms.Core/View.cs
@@ -3,16 +3,17 @@ using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Linq;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
 	public class View : VisualElement, IViewController
 	{
 		public static readonly BindableProperty VerticalOptionsProperty = BindableProperty.Create("VerticalOptions", typeof(LayoutOptions), typeof(View), LayoutOptions.Fill,
-			propertyChanged: (bindable, oldvalue, newvalue) => ((View)bindable).InvalidateMeasure(InvalidationTrigger.VerticalOptionsChanged));
+			propertyChanged: (bindable, oldvalue, newvalue) => ((View)bindable).InvalidateMeasureInternal(InvalidationTrigger.VerticalOptionsChanged));
 
 		public static readonly BindableProperty HorizontalOptionsProperty = BindableProperty.Create("HorizontalOptions", typeof(LayoutOptions), typeof(View), LayoutOptions.Fill,
-			propertyChanged: (bindable, oldvalue, newvalue) => ((View)bindable).InvalidateMeasure(InvalidationTrigger.HorizontalOptionsChanged));
+			propertyChanged: (bindable, oldvalue, newvalue) => ((View)bindable).InvalidateMeasureInternal(InvalidationTrigger.HorizontalOptionsChanged));
 
 		public static readonly BindableProperty MarginProperty = BindableProperty.Create("Margin", typeof(Thickness), typeof(View), default(Thickness), propertyChanged: MarginPropertyChanged);
 
@@ -100,7 +101,7 @@ namespace Xamarin.Forms
 
 		static void MarginPropertyChanged(BindableObject bindable, object oldValue, object newValue)
 		{
-			((View)bindable).InvalidateMeasure(InvalidationTrigger.MarginChanged);
+			((View)bindable).InvalidateMeasureInternal(InvalidationTrigger.MarginChanged);
 		}
 
 		void ValidateGesture(IGestureRecognizer gesture)
diff --git a/Xamarin.Forms.Core/VisualElement.cs b/Xamarin.Forms.Core/VisualElement.cs
index e93dea6c..da8b8292 100644
--- a/Xamarin.Forms.Core/VisualElement.cs
+++ b/Xamarin.Forms.Core/VisualElement.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms
 {
@@ -353,7 +354,7 @@ namespace Xamarin.Forms
 					return;
 				_isNativeStateConsistent = value;
 				if (value && IsPlatformEnabled)
-					InvalidateMeasure(InvalidationTrigger.RendererReady);
+					InvalidateMeasureInternal(InvalidationTrigger.RendererReady);
 			}
 		}
 
@@ -367,7 +368,7 @@ namespace Xamarin.Forms
 
 				_isPlatformEnabled = value;
 				if (value && IsNativeStateConsistent)
-					InvalidateMeasure(InvalidationTrigger.RendererReady);
+					InvalidateMeasureInternal(InvalidationTrigger.RendererReady);
 
 				OnIsPlatformEnabledChanged();
 			}
@@ -428,7 +429,7 @@ namespace Xamarin.Forms
 
 		void IVisualElementController.NativeSizeChanged()
 		{
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		public event EventHandler ChildrenReordered;
@@ -559,9 +560,9 @@ namespace Xamarin.Forms
 
 		public event EventHandler<FocusEventArgs> Unfocused;
 
-		protected virtual void InvalidateMeasure()
+		protected virtual void InvalidateMeasureInternal()
 		{
-			InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			InvalidateMeasureInternal(InvalidationTrigger.MeasureChanged);
 		}
 
 		protected override void OnChildAdded(Element child)
@@ -647,12 +648,17 @@ namespace Xamarin.Forms
 
 		internal event EventHandler<FocusRequestArgs> FocusChangeRequested;
 
-		internal virtual void InvalidateMeasure(InvalidationTrigger trigger)
+		internal virtual void InvalidateMeasureInternal(InvalidationTrigger trigger)
 		{
 			_measureCache.Clear();
 			MeasureInvalidated?.Invoke(this, new InvalidationEventArgs(trigger));
 		}
 
+		void IVisualElementController.InvalidateMeasure(InvalidationTrigger trigger)
+		{
+			InvalidateMeasureInternal(trigger);
+		}
+
 		internal void MockBounds(Rectangle bounds)
 		{
 			_mockX = bounds.X;
@@ -672,7 +678,7 @@ namespace Xamarin.Forms
 
 		internal virtual void OnIsVisibleChanged(bool oldValue, bool newValue)
 		{
-			InvalidateMeasure(InvalidationTrigger.Undefined);
+			InvalidateMeasureInternal(InvalidationTrigger.Undefined);
 		}
 
 		internal override void OnParentResourcesChanged(IEnumerable<KeyValuePair<string, object>> values)
@@ -746,7 +752,7 @@ namespace Xamarin.Forms
 			}
 
 			element.SelfConstraint = constraint;
-			((VisualElement)bindable).InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
+			((VisualElement)bindable).InvalidateMeasureInternal(InvalidationTrigger.SizeRequestChanged);
 		}
 
 		void OnUnfocus()
diff --git a/Xamarin.Forms.Core/Xamarin.Forms.Core.csproj b/Xamarin.Forms.Core/Xamarin.Forms.Core.csproj
index 1deca238..24160a53 100644
--- a/Xamarin.Forms.Core/Xamarin.Forms.Core.csproj
+++ b/Xamarin.Forms.Core/Xamarin.Forms.Core.csproj
@@ -126,7 +126,7 @@
     <Compile Include="ImageSourceConverter.cs" />
     <Compile Include="INavigation.cs" />
     <Compile Include="InvalidationEventArgs.cs" />
-    <Compile Include="InvalidationTrigger.cs" />
+    <Compile Include="Internals\InvalidationTrigger.cs" />
     <Compile Include="InvalidNavigationException.cs" />
     <Compile Include="IOpenGlViewController.cs" />
     <Compile Include="IPanGestureController.cs" />
diff --git a/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs
index 49abc02a..2036e4bb 100644
--- a/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/NativeViewWrapperRenderer.cs
@@ -1,3 +1,5 @@
+using Xamarin.Forms.Internals;
+
 namespace Xamarin.Forms.Platform.Android
 {
 	public class NativeViewWrapperRenderer : ViewRenderer<NativeViewWrapper, global::Android.Views.View>
@@ -22,7 +24,7 @@ namespace Xamarin.Forms.Platform.Android
 			if (e.OldElement == null)
 			{
 				SetNativeControl(Element.NativeView);
-				Control.LayoutChange += (sender, args) => Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				Control.LayoutChange += (sender, args) => ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 			}
 		}
 
diff --git a/Xamarin.Forms.Platform.WP8/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.WP8/NativeViewWrapperRenderer.cs
index e28dec94..e47a6ca0 100644
--- a/Xamarin.Forms.Platform.WP8/NativeViewWrapperRenderer.cs
+++ b/Xamarin.Forms.Platform.WP8/NativeViewWrapperRenderer.cs
@@ -1,4 +1,5 @@
 using System.Windows;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms.Platform.WinPhone
 {
@@ -55,7 +56,7 @@ namespace Xamarin.Forms.Platform.WinPhone
 			if (e.OldElement == null)
 			{
 				SetNativeControl(Element.NativeElement);
-				Control.LayoutUpdated += (sender, args) => { Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); };
+				Control.LayoutUpdated += (sender, args) => { ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); };
 			}
 		}
 	}
diff --git a/Xamarin.Forms.Platform.WP8/ProgressBarRenderer.cs b/Xamarin.Forms.Platform.WP8/ProgressBarRenderer.cs
index b027d674..293d2d0e 100644
--- a/Xamarin.Forms.Platform.WP8/ProgressBarRenderer.cs
+++ b/Xamarin.Forms.Platform.WP8/ProgressBarRenderer.cs
@@ -1,5 +1,6 @@
 using System.ComponentModel;
 using System.Windows;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms.Platform.WinPhone
 {
@@ -29,7 +30,7 @@ namespace Xamarin.Forms.Platform.WinPhone
 
 		void ProgressBarOnValueChanged(object sender, RoutedPropertyChangedEventArgs<double> routedPropertyChangedEventArgs)
 		{
-			Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.WP8/ViewToRendererConverter.cs b/Xamarin.Forms.Platform.WP8/ViewToRendererConverter.cs
index 49b232a1..28f5f8c4 100644
--- a/Xamarin.Forms.Platform.WP8/ViewToRendererConverter.cs
+++ b/Xamarin.Forms.Platform.WP8/ViewToRendererConverter.cs
@@ -2,6 +2,7 @@
 using System.Globalization;
 using System.Windows;
 using System.Windows.Controls;
+using Xamarin.Forms.Internals;
 
 namespace Xamarin.Forms.Platform.WinPhone
 {
@@ -40,7 +41,7 @@ namespace Xamarin.Forms.Platform.WinPhone
 				{
 					frameworkElement.Loaded += (sender, args) =>
 					{
-						_view.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+						((IVisualElementController)_view).InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 						InvalidateMeasure();
 					};
 				}
diff --git a/Xamarin.Forms.Platform.WinRT/DatePickerRenderer.cs b/Xamarin.Forms.Platform.WinRT/DatePickerRenderer.cs
index 88df5cbc..646d7d33 100644
--- a/Xamarin.Forms.Platform.WinRT/DatePickerRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/DatePickerRenderer.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -85,12 +86,12 @@ namespace Xamarin.Forms.Platform.WinRT
 			if (currentDate != e.NewDate.Date) // Match coerced value
 				UpdateDate(currentDate);
 
-			Element.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
+			((IVisualElementController)Element).InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
 		}
 
 		void PickerOnForceInvalidate(object sender, EventArgs eventArgs)
 		{
-			Element?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
 		}
 
 		void UpdateDate(DateTime date)
diff --git a/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs b/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
index 29368aaf..3807570d 100644
--- a/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/ImageRenderer.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Media;
 using Windows.UI.Xaml.Media.Imaging;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -90,7 +91,7 @@ namespace Xamarin.Forms.Platform.WinRT
 
 		void RefreshImage()
 		{
-			Element?.InvalidateMeasure(InvalidationTrigger.RendererReady);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.RendererReady);
 		}
 
 		void UpdateAspect()
diff --git a/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs
index 0e669774..b7e70d0f 100644
--- a/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/NativeViewWrapperRenderer.cs
@@ -1,4 +1,5 @@
 using Windows.UI.Xaml;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -67,7 +68,7 @@ namespace Xamarin.Forms.Platform.WinRT
 			if (e.OldElement == null)
 			{
 				SetNativeControl(Element.NativeElement);
-				Control.LayoutUpdated += (sender, args) => { Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); };
+				Control.LayoutUpdated += (sender, args) => { ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged); };
 			}
 		}
 	}
diff --git a/Xamarin.Forms.Platform.WinRT/PickerRenderer.cs b/Xamarin.Forms.Platform.WinRT/PickerRenderer.cs
index e37b79a1..7095333a 100644
--- a/Xamarin.Forms.Platform.WinRT/PickerRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/PickerRenderer.cs
@@ -5,6 +5,7 @@ using Windows.UI.Core;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -97,7 +98,7 @@ namespace Xamarin.Forms.Platform.WinRT
 			if (!Control.IsFullScreen)
 			{
 				// Force a final redraw after the closing animation has completed
-				Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 			}
 		}
 
@@ -119,7 +120,7 @@ namespace Xamarin.Forms.Platform.WinRT
 				}
 				else
 				{
-					Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+					((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 				}
 			}
 			else
@@ -127,7 +128,7 @@ namespace Xamarin.Forms.Platform.WinRT
 				// The ComboBox is now closed; if we were animating the closure, stop
 				_isAnimating = false;
 				// and force the final redraw
-				Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 			}
 		}
 
@@ -144,7 +145,7 @@ namespace Xamarin.Forms.Platform.WinRT
 				while (_isAnimating)
 				{
 					await Task.Delay(16);
-					await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged));
+					await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () => ((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged));
 				}
 			});
 		}
diff --git a/Xamarin.Forms.Platform.WinRT/ProgressBarRenderer.cs b/Xamarin.Forms.Platform.WinRT/ProgressBarRenderer.cs
index 87f1e35e..b805b2f6 100644
--- a/Xamarin.Forms.Platform.WinRT/ProgressBarRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/ProgressBarRenderer.cs
@@ -1,5 +1,6 @@
 using System.ComponentModel;
 using Windows.UI.Xaml.Controls.Primitives;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -53,7 +54,7 @@ namespace Xamarin.Forms.Platform.WinRT
 
 		void ProgressBarOnValueChanged(object sender, RangeBaseValueChangedEventArgs rangeBaseValueChangedEventArgs)
 		{
-			Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 		}
 	}
 }
\ No newline at end of file
diff --git a/Xamarin.Forms.Platform.WinRT/TimePickerRenderer.cs b/Xamarin.Forms.Platform.WinRT/TimePickerRenderer.cs
index 8c878b29..0095cdc4 100644
--- a/Xamarin.Forms.Platform.WinRT/TimePickerRenderer.cs
+++ b/Xamarin.Forms.Platform.WinRT/TimePickerRenderer.cs
@@ -3,6 +3,7 @@ using System.ComponentModel;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
 using Windows.UI.Xaml.Media;
+using Xamarin.Forms.Internals;
 
 #if WINDOWS_UWP
 
@@ -77,12 +78,12 @@ namespace Xamarin.Forms.Platform.WinRT
 		void OnControlTimeChanged(object sender, TimePickerValueChangedEventArgs e)
 		{
 			Element.Time = e.NewTime;
-			Element?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
 		}
 
 		void PickerOnForceInvalidate(object sender, EventArgs eventArgs)
 		{
-			Element?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
+			((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.SizeRequestChanged);
 		}
 
 		void UpdateTime()
diff --git a/Xamarin.Forms.Platform.iOS/NativeViewWrapperRenderer.cs b/Xamarin.Forms.Platform.iOS/NativeViewWrapperRenderer.cs
index b21c8593..58cacdc6 100644
--- a/Xamarin.Forms.Platform.iOS/NativeViewWrapperRenderer.cs
+++ b/Xamarin.Forms.Platform.iOS/NativeViewWrapperRenderer.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using Xamarin.Forms.Internals;
 #if __UNIFIED__
 using CoreGraphics;
 using UIKit;
@@ -33,7 +34,7 @@ namespace Xamarin.Forms.Platform.iOS
 		{
 			if (Element?.LayoutSubViews == null)
 			{
-				Element?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
+				((IVisualElementController)Element)?.InvalidateMeasure(InvalidationTrigger.MeasureChanged);
 				base.LayoutSubviews();
 				return;
 			}
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms.Internals/InvalidationTrigger.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms.Internals/InvalidationTrigger.xml
new file mode 100644
index 00000000..345d841a
--- /dev/null
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms.Internals/InvalidationTrigger.xml
@@ -0,0 +1,120 @@
+<Type Name="InvalidationTrigger" FullName="Xamarin.Forms.Internals.InvalidationTrigger">
+  <TypeSignature Language="C#" Value="public enum InvalidationTrigger" />
+  <TypeSignature Language="ILAsm" Value=".class public auto ansi sealed InvalidationTrigger extends System.Enum" />
+  <AssemblyInfo>
+    <AssemblyName>Xamarin.Forms.Core</AssemblyName>
+    <AssemblyVersion>2.0.0.0</AssemblyVersion>
+  </AssemblyInfo>
+  <Base>
+    <BaseTypeName>System.Enum</BaseTypeName>
+  </Base>
+  <Attributes>
+    <Attribute>
+      <AttributeName>System.Flags</AttributeName>
+    </Attribute>
+  </Attributes>
+  <Docs>
+    <summary>To be added.</summary>
+    <remarks>To be added.</remarks>
+  </Docs>
+  <Members>
+    <Member MemberName="HorizontalOptionsChanged">
+      <MemberSignature Language="C#" Value="HorizontalOptionsChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger HorizontalOptionsChanged = int32(2)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="MarginChanged">
+      <MemberSignature Language="C#" Value="MarginChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger MarginChanged = int32(32)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="MeasureChanged">
+      <MemberSignature Language="C#" Value="MeasureChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger MeasureChanged = int32(1)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="RendererReady">
+      <MemberSignature Language="C#" Value="RendererReady" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger RendererReady = int32(16)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="SizeRequestChanged">
+      <MemberSignature Language="C#" Value="SizeRequestChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger SizeRequestChanged = int32(8)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="Undefined">
+      <MemberSignature Language="C#" Value="Undefined" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger Undefined = int32(0)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="VerticalOptionsChanged">
+      <MemberSignature Language="C#" Value="VerticalOptionsChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.Internals.InvalidationTrigger VerticalOptionsChanged = int32(4)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.Internals.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+  </Members>
+</Type>
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms/IVisualElementController.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms/IVisualElementController.xml
index a2b63a36..0b465dc2 100644
--- a/docs/Xamarin.Forms.Core/Xamarin.Forms/IVisualElementController.xml
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms/IVisualElementController.xml
@@ -18,6 +18,25 @@
     <remarks>To be added.</remarks>
   </Docs>
   <Members>
+    <Member MemberName="InvalidateMeasure">
+      <MemberSignature Language="C#" Value="public void InvalidateMeasure (Xamarin.Forms.Internals.InvalidationTrigger trigger);" />
+      <MemberSignature Language="ILAsm" Value=".method public hidebysig newslot virtual instance void InvalidateMeasure(valuetype Xamarin.Forms.Internals.InvalidationTrigger trigger) cil managed" />
+      <MemberType>Method</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Void</ReturnType>
+      </ReturnValue>
+      <Parameters>
+        <Parameter Name="trigger" Type="Xamarin.Forms.Internals.InvalidationTrigger" />
+      </Parameters>
+      <Docs>
+        <param name="trigger">To be added.</param>
+        <summary>To be added.</summary>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="NativeSizeChanged">
       <MemberSignature Language="C#" Value="public void NativeSizeChanged ();" />
       <MemberSignature Language="ILAsm" Value=".method public hidebysig newslot virtual instance void NativeSizeChanged() cil managed" />
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms/InvalidationTrigger.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms/InvalidationTrigger.xml
new file mode 100644
index 00000000..b75a5a71
--- /dev/null
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms/InvalidationTrigger.xml
@@ -0,0 +1,120 @@
+<Type Name="InvalidationTrigger" FullName="Xamarin.Forms.InvalidationTrigger">
+  <TypeSignature Language="C#" Value="public enum InvalidationTrigger" />
+  <TypeSignature Language="ILAsm" Value=".class public auto ansi sealed InvalidationTrigger extends System.Enum" />
+  <AssemblyInfo>
+    <AssemblyName>Xamarin.Forms.Core</AssemblyName>
+    <AssemblyVersion>2.0.0.0</AssemblyVersion>
+  </AssemblyInfo>
+  <Base>
+    <BaseTypeName>System.Enum</BaseTypeName>
+  </Base>
+  <Attributes>
+    <Attribute>
+      <AttributeName>System.Flags</AttributeName>
+    </Attribute>
+  </Attributes>
+  <Docs>
+    <summary>To be added.</summary>
+    <remarks>To be added.</remarks>
+  </Docs>
+  <Members>
+    <Member MemberName="HorizontalOptionsChanged">
+      <MemberSignature Language="C#" Value="HorizontalOptionsChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger HorizontalOptionsChanged = int32(2)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="MarginChanged">
+      <MemberSignature Language="C#" Value="MarginChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger MarginChanged = int32(32)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="MeasureChanged">
+      <MemberSignature Language="C#" Value="MeasureChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger MeasureChanged = int32(1)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="RendererReady">
+      <MemberSignature Language="C#" Value="RendererReady" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger RendererReady = int32(16)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="SizeRequestChanged">
+      <MemberSignature Language="C#" Value="SizeRequestChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger SizeRequestChanged = int32(8)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="Undefined">
+      <MemberSignature Language="C#" Value="Undefined" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger Undefined = int32(0)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+    <Member MemberName="VerticalOptionsChanged">
+      <MemberSignature Language="C#" Value="VerticalOptionsChanged" />
+      <MemberSignature Language="ILAsm" Value=".field public static literal valuetype Xamarin.Forms.InvalidationTrigger VerticalOptionsChanged = int32(4)" />
+      <MemberType>Field</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>Xamarin.Forms.InvalidationTrigger</ReturnType>
+      </ReturnValue>
+      <Docs>
+        <summary>To be added.</summary>
+      </Docs>
+    </Member>
+  </Members>
+</Type>
diff --git a/docs/Xamarin.Forms.Core/Xamarin.Forms/VisualElement.xml b/docs/Xamarin.Forms.Core/Xamarin.Forms/VisualElement.xml
index bd8e615b..732f2d00 100644
--- a/docs/Xamarin.Forms.Core/Xamarin.Forms/VisualElement.xml
+++ b/docs/Xamarin.Forms.Core/Xamarin.Forms/VisualElement.xml
@@ -512,7 +512,6 @@
         <AssemblyVersion>1.3.0.0</AssemblyVersion>
         <AssemblyVersion>1.4.0.0</AssemblyVersion>
         <AssemblyVersion>1.5.0.0</AssemblyVersion>
-        <AssemblyVersion>2.0.0.0</AssemblyVersion>
       </AssemblyInfo>
       <ReturnValue>
         <ReturnType>System.Void</ReturnType>
@@ -523,6 +522,22 @@
         <remarks>To be added.</remarks>
       </Docs>
     </Member>
+    <Member MemberName="InvalidateMeasureInternal">
+      <MemberSignature Language="C#" Value="protected virtual void InvalidateMeasureInternal ();" />
+      <MemberSignature Language="ILAsm" Value=".method familyhidebysig newslot virtual instance void InvalidateMeasureInternal() cil managed" />
+      <MemberType>Method</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Void</ReturnType>
+      </ReturnValue>
+      <Parameters />
+      <Docs>
+        <summary>To be added.</summary>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="IsEnabled">
       <MemberSignature Language="C#" Value="public bool IsEnabled { get; set; }" />
       <MemberSignature Language="ILAsm" Value=".property instance bool IsEnabled" />
@@ -1829,6 +1844,25 @@
         <remarks>The x value of an element is set during the Layout phase.</remarks>
       </Docs>
     </Member>
+    <Member MemberName="Xamarin.Forms.IVisualElementController.InvalidateMeasure">
+      <MemberSignature Language="C#" Value="void IVisualElementController.InvalidateMeasure (Xamarin.Forms.Internals.InvalidationTrigger trigger);" />
+      <MemberSignature Language="ILAsm" Value=".method hidebysig newslot virtual instance void Xamarin.Forms.IVisualElementController.InvalidateMeasure(valuetype Xamarin.Forms.Internals.InvalidationTrigger trigger) cil managed" />
+      <MemberType>Method</MemberType>
+      <AssemblyInfo>
+        <AssemblyVersion>2.0.0.0</AssemblyVersion>
+      </AssemblyInfo>
+      <ReturnValue>
+        <ReturnType>System.Void</ReturnType>
+      </ReturnValue>
+      <Parameters>
+        <Parameter Name="trigger" Type="Xamarin.Forms.Internals.InvalidationTrigger" />
+      </Parameters>
+      <Docs>
+        <param name="trigger">To be added.</param>
+        <summary>To be added.</summary>
+        <remarks>To be added.</remarks>
+      </Docs>
+    </Member>
     <Member MemberName="Xamarin.Forms.IVisualElementController.NativeSizeChanged">
       <MemberSignature Language="C#" Value="void IVisualElementController.NativeSizeChanged ();" />
       <MemberSignature Language="ILAsm" Value=".method hidebysig newslot virtual instance void Xamarin.Forms.IVisualElementController.NativeSizeChanged() cil managed" />