Add policy for 'debug.tracing.desktop_mode_visible_tasks' system
property

The property will be used to hold the number of visible windows when
in desktop mode. It will be written by com.android.systemui and
read by perfetto to set the initial value of a counter in traces.

Bug: 358369221
Test: Verified on device
Change-Id: Iad8dc7a66765856ee7affb707f2dba6c1bbfbf49
diff --git a/private/traced_probes.te b/private/traced_probes.te
index 003e992..6540420 100644
--- a/private/traced_probes.te
+++ b/private/traced_probes.te
@@ -111,6 +111,10 @@
 binder_call(traced_probes, statsd)
 allow traced_probes stats_service:service_manager find;
 
+# Allow reading the system property representing number of desktop windows to
+# set the initial value for the counter in traces.
+get_prop(traced_probes, debug_tracing_desktop_mode_visible_tasks_prop)
+
 ###
 ### Neverallow rules
 ###