Merge "Always call back when printer changes" into rvc-dev

        // Add the new printers, i.e. what is left.

        printers.addAll(discoveredPrinters.values());

        // Do nothing if the printer list is not changed.

        if (Objects.equals(mPrinters, printers)) {

            return;

        }

        // Update the list of printers.

        mPrinters.clear();

        mPrinters.addAll(printers);