C# Baseline function

Summary:
same as Measure function, based on #317
Closes https://github.com/facebook/yoga/pull/321

Reviewed By: emilsjolander

Differential Revision: D4385336

Pulled By: splhack

fbshipit-source-id: b583ec79861d2e9abba31a72503e2f706bfda8e8

csharp/Facebook.Yoga/YogaBaselineFunc.cs

@@ -0,0 +1,17 @@
+/**
+ * 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;
+using System.Runtime.InteropServices;
+
+namespace Facebook.Yoga
+{
+    [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
+    public delegate float YogaBaselineFunc(IntPtr node, float width, float height);
+}