Export shaka.util.StreamUtils.meetsRestrictions function for use in custom AbrManager(s)

[fernandoneira]

Have you read the FAQ and checked for duplicate open issues?

Is your feature request related to a problem? Please describe.
I'm implementing a custom AbrManager. As such, I notice that I can benefit greatly from having access to shaka.util.StreamUtils.meetsRestrictions, otherwise I have to duplicate most of its functionality, with the added complexity on my side.
Shaka's own SimpleAbrManager uses this internally - in fact, this is the only current usage besides other StreamUtils functions.

Describe the solution you'd like
Annotate shaka.util.StreamUtils.meetsRestrictions for export.

Describe alternatives you've considered
Duplicate the implementation on my end.

Additional context
My custom AbrManager is similar to SimpleAbrManager - in fact extends it - but covers some additional scenarios, for which it is convenient to be able to check variants for restrictions.