From d794e285ab966391b508b8df618a9b2fe72b572d Mon Sep 17 00:00:00 2001
From: Jihye Hong <jh.hong@lge.com>
Date: Sun, 1 Jul 2018 17:45:07 +0900
Subject: [PATCH] Add using registerProperty

- Register the syntax of "--spatial-navigation-contain'
---
 polyfill/spatnav-api.js | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/polyfill/spatnav-api.js b/polyfill/spatnav-api.js
index 36b5d8aeb32..d40c68bf33b 100644
--- a/polyfill/spatnav-api.js
+++ b/polyfill/spatnav-api.js
@@ -19,6 +19,20 @@
     this._options = options;
   }
 
+  /**
+  * CSS.registerProperty() from the Properties and Values API
+  * Reference: https://drafts.css-houdini.org/css-properties-values-api/#the-registerproperty-function
+  */
+  if (window.CSS && CSS.registerProperty) {
+    console.log("registerProperty is available");
+    CSS.registerProperty({
+      name: '--spatial-navigation-contain',
+      syntax: 'auto | contain',
+      inherits: false,
+      initialValue: 'auto'
+    });
+  }
+
   /**
   * Gives a CSS custom property value applied at the element
   * @function