I think we may continue to need them. The `matcher` that gets passed to the `listener` by `window.matchMedia` is actually the same matcher object that we initially create. When `_this.set(name, matcher)` is called, Ember thinks it's the same object and that nothing has changed, even though `matcher.matches` may have changed.

That was the rationale for the test below (`matcher's name property can be bound to`), which actually passes the *same* object each time to the listener. We wanted to ensure that Ember would consider that a new, dirty value.