* infrun.c (struct inferior_status): Replace fields

* infrun.c (struct inferior_status): Replace fields
selected_frame_address and selected_level with field
selected_frame_id.
(save_inferior_status): Update.  Use get_frame_id.
(struct restore_selected_frame_args): Delete.
(restore_selected_frame): Update.  Use frame_find_by_id.
(restore_inferior_status): Update.

* breakpoint.h (struct breakpoint): Change type of
watchpoint_frame to frame_id.
* breakpoint.c (insert_breakpoints): Use frame_find_by_id.  Remove
call to get_current_frame.
(do_enable_breakpoint): Use frame_find_by_id.  Remove call to
get_current_frame.
(watchpoint_check): Use frame_find_by_id.

* frame.h (record_selected_frame): Delete declaration.
* stack.c (record_selected_frame): Delete function.

* frame.h (struct frame_id): Define.
(get_frame_id): Declare.
(frame_find_by_id): Declare.
* frame.c (frame_find_by_id): New function.
(get_frame_id): New function.