Bug 23933 - Proposal: Change constraints to use WebIDL dictionaries

I am opposed to this.  It makes the concept of 'mandatory' meaningless, and thus requires the app to examine  every device it gets back to make sure that it actually meets the constraints.

I do agree that unknown mandatory constraints should be treated somewhat differently, and  think that there is a simple way to do this: in the case of an unknown mandatory constraint return an indication to the app (via the error callback) that the call failed because  of an unknown mandatory constraint.  Since the user has not yet been prompted at this point, the app can decide whether to give up silently or to remove the unknown constraint and try again.   The app now has full control and can decide whether or not  to ignore the unknown mandatory constraint.  That's better than having the UA make that decision for it in a blunderbuss manner.


-          Jim