Allow only system_server to read uid_time_in_state

Bug: 62706738
Bug: 34133340
Test: Check that uid_time_in_state can't be read from
the shell without root permissions and that
"dumpsys batterystats --checkin| grep ctf" shows frequency
data (system_server was able to read uid_time_in_state)

Change-Id: Ic6a54da4ebcc9e10b0e3af8f14a45d7408e8686e
(cherry picked from commit 4dc88795d0906148e3414688fa81481b4edaacff)
diff --git a/private/genfs_contexts b/private/genfs_contexts
index c2cfa2c..5c5dd89 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -40,6 +40,7 @@
 genfscon proc /uid_cputime/remove_uid_range u:object_r:proc_uid_cputime_removeuid:s0
 genfscon proc /uid_io/stats u:object_r:proc_uid_io_stats:s0
 genfscon proc /uid_procstat/set u:object_r:proc_uid_procstat_set:s0
+genfscon proc /uid_time_in_state u:object_r:proc_uid_time_in_state:s0
 genfscon proc /zoneinfo u:object_r:proc_zoneinfo:s0
 
 # selinuxfs booleans can be individually labeled.
diff --git a/private/system_server.te b/private/system_server.te
index 7b95600..6f1579b 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -126,6 +126,9 @@
 # Write /proc/uid_procstat/set.
 allow system_server proc_uid_procstat_set:file { w_file_perms getattr };
 
+# Read /proc/uid_time_in_state.
+allow system_server proc_uid_time_in_state:file r_file_perms;
+
 # Write to /proc/sysrq-trigger.
 allow system_server proc_sysrq:file rw_file_perms;