Embedded mode scrolls enclosing page when arrow keys are pressed

Description: There is no way to lock arrow key input to go to the A-Frame embedded view without going into fullscreen mode, and as a result, pressing the up/down arrow keys scrolls the page it's embedded in. This is actually evident in the A-Frame website itself.

Here is an example of a workaround you can do if you own the website you are embedding the A-Frame in. It involves checking whether the user has clicked on the body or the a-scene element and "freeing" or "freezing" the scroll accordingly. https://glitch.com/edit/#!/kiwi-magpie

I also had a question about whether the way A-Frame captures keyboard input is compliant with accessibility standards. I don't know enough about the standards to formulate a more specific question though. scratches head

• A-Frame Version: 0.8.0
• Platform / Device: 2015 MacBook Pro 15", Safari 11.1
• Reproducible Code Snippet or URL: https://aframe.io/docs/0.8.0/components/embedded.html

Reproduce the behavior on the A-Frame embedded documentation page at https://aframe.io/docs/0.8.0/components/embedded.html, then compare it with the focus and scroll workaround shown in the linked Glitch example. Identify the embedded-mode keyboard entry point and verify that arrow keys no longer scroll the enclosing page while the embedded view is active.