update c# interop to use percentage

csharp/Facebook.Yoga/YogaValue.cs

@@ -0,0 +1,67 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+using System.Runtime.InteropServices;
+
+namespace Facebook.Yoga
+{
+    [StructLayout(LayoutKind.Sequential)]
+    public struct YogaValue
+    {
+        private float Value;
+        private YogaUnit Unit;
+        private byte isDefined;
+
+        public bool IsDefined => isDefined != 0;
+
+        public static YogaValue Pixel(float value)
+        {
+            return new YogaValue
+            {
+                Value = value,
+                isDefined = 1,
+                Unit = YogaUnit.Pixel
+            };
+        }
+
+        public bool Equals(YogaValue other)
+        {
+            return Value.Equals(other.Value) && Unit == other.Unit;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) return false;
+            return obj is YogaValue && Equals((YogaValue) obj);
+        }
+
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                return (Value.GetHashCode() * 397) ^ (int) Unit;
+            }
+        }
+
+        public static YogaValue Percent(float value)
+        {
+            return new YogaValue
+            {
+                Value = value,
+                isDefined = 1,
+                Unit = YogaUnit.Percent
+            };
+        }
+
+        public static implicit operator YogaValue(float pixelValue)
+        {
+            return Pixel(pixelValue);
+        }
+    }
+}