https://github.com/mozilla-b2g/gaia/pull/10129/files#L0R1372 checkbox, so it's boolean?
https://github.com/mozilla-b2g/gaia/pull/10129/files#L2R84 set boolean to _globalOrientation
https://github.com/mozilla-b2g/gaia/pull/10129/files#L2R910 
`screen.mozLockOrientation(_globalOrientation);` Wat?