Allow perfetto traced_probes to poll /proc/{meminfo,stat,vmstat,...}

This allows the trace producer daemon to snapshot counters at
high frequency in the trace. As usual for Perfetto, this data is
NOT made available to arbitrary apps but only to an extremely
limited subset of processes governed by selinux rules (currently
shell and statsd).

Bug: 115956288
Change-Id: I7e1bfda4b568b9bac9012b198ecbb998da4f773d
1 file changed