Replace standard cardboard splash screen

[Pixelatex]

Hello,

We're missing an id or class name on the div created by 'rotate-instructions.js'. This would allow you to target it and efficiently replace it with a splash screen of our own choosing to keep the styling of the app consistent. The only way to do this now is a bit hacky and not really best practice.

Replacing the content seems to break it because it requires the structure. So now the only way to replace the standard splash screen is to overlay one on top of the existing one. A way to fix this would be really appreciated. Like some id's on the icon, button, etc..

I'm aware this isn't really a major issue because it functions perfectly without but for the designers who like to keep their design consistent, this is a real eyesore.

[jsantell]

Something to look into -- I don't think it's within the realm of the polyfill for this to be too configurable and stylable, as it's specifically for the CardboardVRDisplay (can't style native displays), it should be possible to hook into the DOM here.