trace-cmd: allow for custom show and handle init

External applications that need to hook into the streaming infrastructure need a
way to have the handle init'ed in a specific way and need a way to provide their
own read function so they can intercept events.  This patch adds the neccessary
definitions and hooks.  Thanks,

Link: http://lkml.kernel.org/r/1448053053-24188-6-git-send-email-jbacik@fb.com

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
7 files changed