Gracefully handles when Document's Permission Policy does not allow c…

…alling getGamepads() from the context (such as an IFRAME).

src/systems/tracked-controls-webvr.js

@@ -41,26 +41,30 @@ module.exports.System = registerSystem('tracked-controls-webvr', {
  * Update controller list.
  */
  updateControllerList: function () {
- var controllers = this.controllers;
- var gamepad;
- var gamepads;
- var i;
- var prevCount;
+ try {
+ var controllers = this.controllers;
+ var gamepad;
+ var gamepads;
+ var i;
+ var prevCount;
 
- gamepads = navigator.getGamepads && navigator.getGamepads();
- if (!gamepads) { return; }
+  gamepads = navigator.getGamepads && navigator.getGamepads();
+  if (!gamepads) { return; }
 
- prevCount = controllers.length;
- controllers.length = 0;
- for (i = 0; i < gamepads.length; ++i) {
- gamepad = gamepads[i];
- if (gamepad && gamepad.pose) {
- controllers.push(gamepad);
+ prevCount = controllers.length;
+ controllers.length = 0;
+ for (i = 0; i < gamepads.length; ++i) {
+ gamepad = gamepads[i];
+ if (gamepad && gamepad.pose) {
+ controllers.push(gamepad);
+ }
  }
- }
 
- if (controllers.length !== prevCount) {
- this.el.emit('controllersupdated', undefined, false);
+ if (controllers.length !== prevCount) {
+ this.el.emit('controllersupdated', undefined, false);
+ }
+ } catch (e) {
+ console.warn('can\'t update controller list:', e);
  }
  }
 });