Collection changed callback does not respect input or output as device type

[achronop]

Registering a callback for input or output collection change is supported by Linux backends (both C and rust). The following code should be supported:

  int rv = cubeb_register_device_collection_changed(GetCubebContext(),
       static_cast<cubeb_device_type>(CUBEB_DEVICE_TYPE_INPUT | CUBEB_DEVICE_TYPE_OUTPUT),
       &mozilla::CubebDeviceEnumerator::AudioDeviceListChanged_s, this);

With cubeb remote on, the collection change callback is not triggered on plug or unplug. However, the method returns CUBEB_OK and does not give the opportunity to the client to workaround the missing callback.

[kinetiknz]

Note to self: cubeb_stream_register_device_changed_callback is also unimplemented.

[kinetiknz]

Note to self: this needs to be based on the changes made in BMO 1498242

[kinetiknz]

9600391 merged Alex's patch that at least fixed the wrong error code. Actual implementation of the callbacks coming soon.

[kinetiknz]

Closed via #62.