* breakpoint.c (breakpoint_restore_shadows): New OWNER comment.
(should_be_inserted): Return zero also on NULL OWNER.
(breakpoint_program_space_exit): New OWNER comment.
(insert_breakpoint_locations): Extend comment for OWNER.
(remove_breakpoint_1, remove_breakpoint): Assert on OWNER.
(breakpoint_init_inferior, breakpoint_here_p, breakpoint_thread_match):
New OWNER comment.
(print_it_typical): Return PRINT_UNKNOWN on NULL OWNER.
(watchpoint_check): New assert on BREAKPOINT_AT and OWNER.
(bpstat_check_location): New assert on OWNER.
(bpstat_check_watchpoint, bpstat_check_breakpoint_conditions): Move BL
and B initializations to the code block. New assert on them.
(print_one_breakpoint_location): New OWNER comment.
(watchpoint_locations_match): Assert on OWNER.
(breakpoint_locations_match): Move HW_POINT1 and HW_POINT2
initializations to the code block. New assert on OWNER.
(set_breakpoint_location_function): New assert on OWNER.
(disable_breakpoints_in_shlibs, disable_breakpoints_in_unloaded_shlib)
(bp_location_compare, update_global_location_list)
(update_global_location_list): New OWNER comment.
gdb/testsuite/
* gdb.base/moribund-step.exp: New.
