Allow composd to run fd_server

Besides the basic execution that is similar to the (deprecating)
odrefresh case, fd_server also needs to be able to create and change
files in the output directory.

Bug: 205750213
Test: /apex/com.android.compos/bin/composd_cmd forced-odrefresh
      # Saw composd started the fd_server and the VM
Change-Id: Ia66015b72c4bd232c623604be326c7d7145c0a38
diff --git a/private/composd.te b/private/composd.te
index 41f1a9b..88c4e4a 100644
--- a/private/composd.te
+++ b/private/composd.te
@@ -22,10 +22,14 @@
 allow composd apex_compos_data_file:dir create_dir_perms;
 allow composd apex_compos_data_file:file create_file_perms;
 
-# TODO(b/205750213): Removed these when we run odrefresh in the VM
+# TODO(b/209008712): Removed these when we run odrefresh in the VM
 # Run odrefresh to refresh ART artifacts, and kill it if we need to
 domain_auto_trans(composd, odrefresh_exec, odrefresh)
 allow composd odrefresh:process sigkill;
 
+# Run fd_server in its own domain, and send SIGTERM when finished.
+domain_auto_trans(composd, fd_server_exec, compos_fd_server)
+allow composd compos_fd_server:process signal;
+
 # Read ART's properties
 get_prop(composd, dalvik_config_prop)