Out of the TUI logic that allows toggling the presentation of source
code lines.

Will be used in the upcoming --stdio2 mode.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-g0ckz9ajy6unswrv2iy39mxk@git.kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>