Moved iOS GetInnerHeight to its own function

Author: photonstorm

src/dom/GetInnerHeight.js

@@ -0,0 +1,43 @@
+/**
+ * @author       Richard Davey <rich@photonstorm.com>
+ * @copyright    2018 Photon Storm Ltd.
+ * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
+ */
+
+var GetInnerHeight = function (iOS)
+{
+    //  Based on code by @tylerjpeterson
+
+    if (!iOS)
+    {
+        return window.innerHeight;
+    }
+
+    var axis = Math.abs(window.orientation);
+
+    var size = { w: 0, h: 0 };
+    
+    var ruler = document.createElement('div');
+
+    ruler.setAttribute('style', 'position: fixed; height: 100vh; width: 0; top: 0');
+
+    document.documentElement.appendChild(ruler);
+
+    size.w = (axis === 90) ? ruler.offsetHeight : window.innerWidth;
+    size.h = (axis === 90) ? window.innerWidth : ruler.offsetHeight;
+
+    document.documentElement.removeChild(ruler);
+
+    ruler = null;
+
+    if (Math.abs(window.orientation) !== 90)
+    {
+        return size.h;
+    }
+    else
+    {
+        return size.w;
+    }
+};
+
+module.exports = GetInnerHeight;