This is a subtle change. You want null, 0, false and the empty string to be treated as valid keys.

The camera app depends critically on this mostly undocumented framework. You're the only one who really understands it. When you make subtle changes like this without any explanation in a comment or in the commit message or in the bug, it becomes hard to review.

I guess my comment here is: please double check that you meant to do this.  And are you confident that this API change won't affect any other parts of the app?