Move module_set_weight() into ModuleHandler::setWeight(), add ModuleHandler::getWeight() to replace missing functionality

Wondering why there is no corresponding module_get_weight() for module_set_weight(). The typical use case is to set my module's weight to one higher than another module, but I don't necessarily know what the weight of the other module is:

  $weight = (int) db_query("SELECT weight FROM {system} WHERE name = 'dependency'")->fetchField();
  db_update('system')
    ->fields(array('weight' => $weight + 1)) 
    ->condition('name', 'mymodule')
    ->execute();

I don't see a way to possibly do this with the newly-converted code.