Add public PredefinedLayouts

UIX/Microsoft/Iris/ViewItems/ImageLayout.cs

@@ -72,5 +72,16 @@ namespace Microsoft.Iris.ViewItems
         }
 
         void ILayout.Arrange(ILayoutNode layoutNode, LayoutSlot slot) => DefaultLayout.Arrange(layoutNode, slot);
+
+        public bool Equals(ILayout other)
+        {
+            if (other is not ImageLayout o) return false;
+
+            return DefaultChildAlignment == o.DefaultChildAlignment
+                && SourceSize == o.SourceSize
+                && MinimumSize == o.MinimumSize
+                && MaintainAspectRatio == o.MaintainAspectRatio
+                && Fill == o.Fill;
+        }
     }
 }

UIX/Microsoft/Iris/ViewItems/Text.cs

@@ -1430,6 +1430,11 @@ namespace Microsoft.Iris.ViewItems
             text._bits = (uint)((Bits)text._bits & ~changeBit);
         }
 
+        public bool Equals(ILayout other)
+        {
+            return this == other;
+        }
+
         private class MarkedRange
         {
             public string tagName;

UIX/Microsoft/Iris/ViewItems/TextRunRenderer.cs

@@ -115,5 +115,14 @@ namespace Microsoft.Iris.ViewItems
         }
 
         void ILayout.Arrange(ILayoutNode layoutNode, LayoutSlot slot) => DefaultLayout.Arrange(layoutNode, slot);
+
+        public bool Equals(ILayout other)
+        {
+            if (other is not TextRunRenderer o) return false;
+
+            return DefaultChildAlignment == o.DefaultChildAlignment
+                && Color == o.Color
+                && Data.ToString() == o.Data.ToString();
+        }
     }
 }