// adjust choose_args_map weight, preserving the hierarchical summation
// property. used by callers optimizing layouts by tweaking weights.
int _choose_args_adjust_item_weight_in_bucket(
// adjust choose_args_map weight, preserving the hierarchical summation
// property. used by callers optimizing layouts by tweaking weights.
int _choose_args_adjust_item_weight_in_bucket(