Comment 2 for bug 1357429

Note: orientation is simply a message to a surface to say "the current orientation is __" - it does not and should not impact the rendering.

We don't want clients listening for changes to the Screen orientation property, as with multiple clients running, but only 1 visible, they all re-orient their content for no reason which is costly. We prefer that shell can individually tell clients - here's the orientation you're currently showing at. It also helps for tablet, where side stage portrait is actually screen landscape.