* cp-tree.h (CLASSTYPE_VBASECLASSES): Improve documentation.
	* class.c (layout_basetypes): Don't set BINFO_INHERITANCE_CHAIN
	or unshare_base_binfos for virtual bases here.
	* search.c (dfs_get_vbase_types): Do it here.
	(get_vbase_types): Adjust.

From-SVN: r31184