Bug 1057198 - [LockScreen] Make LockScreen in an iframe before make it as an app

I recommend not to use data-frame-origin anymore. It's something related to old window management and we should deprecate it, plus we should not use origin to identify anything.

I will suggest to use #lockscreen > div > iframe to identify the lockscreen iframe, or better we have a library to help a test to identify lockscreen iframe so if any DOM structure changed we will only change one file.