Create Document exitPointerLock and pointerLockElement API methods.

LayoutTests/http/tests/resources/pointer-lock/iframe-common.js

 function thisFileName()
 {
     return window.location.href.split("/").pop();
 }
 
 window.onmessage = function (messageEvent) {
     switch (messageEvent.data[0]) {
     case "eval":
         eval(messageEvent.data[1]);
         break;
     case "pass message down":
         iframe = document.getElementsByTagName("iframe")[0];
         iframe.contentWindow.postMessage(messageEvent.data.slice(1), "*");
         break;
     default:
         // Pass all other messages up to parent.
         parent.postMessage(messageEvent.data, "*");
     }
 }
 
 document.onpointerlockchange = function () {
-    parent.postMessage(thisFileName() + " onpointerlockchange, document.webkitPointerLockElement = " + document.webkitPointerLockElement, "*");
+    parent.postMessage(thisFileName() + " onpointerlockchange, document.pointerLockElement = " + document.pointerLockElement, "*");
 }
 
 document.onpointerlockerror = function () {
     parent.postMessage(thisFileName() + " onpointerlockerror", "*");
 }