BREAKING - Change measure() api to remove need for MeasureOutput allocation

Summary: This is an API breaking change done to allow us to avoid an allocation during measurement. Instead we do the same trick as is done when passing measure results to C, we path them into a long.

Reviewed By: splhack

Differential Revision: D4081037

fbshipit-source-id: 28adbcdd160cbd3f59a0fdd4b9f1200ae18678f1

csharp/Facebook.CSSLayout/MeasureOutput.cs

@@ -1,4 +1,4 @@
-/**
+/**
  * Copyright (c) 2014-present, Facebook, Inc.
  * All rights reserved.
  *
@@ -11,7 +11,19 @@ namespace Facebook.CSSLayout
 {
     public class MeasureOutput
     {
-        public float Width { get; set; }
-        public float Height { get; set; }
+        public static long Make(int width, int height)
+        {
+          return ((long) width) << 32 | ((long) height);
+        }
+
+        public static int GetWidth(long measureOutput)
+        {
+          return (int) (0xFFFFFFFF & (measureOutput >> 32));
+        }
+
+        public static int GetHeight(long measureOutput)
+        {
+          return (int) (0xFFFFFFFF & measureOutput);
+        }
     }
 }