title: iOS Safari's iframe doesn't get device orientation and motion events
body: <p>I was trying to learn about HTML5 device orientation API. I found few demos that worked great on Android and iOS when I opened them on browser.</p>
  
  <p>Demo: <a href="https://www.audero.it/demo/device-orientation-api-demo.html" rel="nofollow">https://www.audero.it/demo/device-orientation-api-demo.html</a></p>
  
  <p>Now, when I included those pages in an iframe and opened in Android (chrome), it worked as expected. But, in iOS safari, the page just didn't do anything. Looks like the <code>window.DeviceOrientationEvent</code> is true, but no <code>deviceorientation</code> event is triggered inside the iframe. </p>
  
  <p>Demo: <a href="http://output.jsbin.com/sumevugiga/1" rel="nofollow">http://output.jsbin.com/sumevugiga/1</a></p>
  
  <p>Is this expected or am I doing something wrong here?</p>