Add fwk_display_hwservice.

This hidl service provides information about vsync and hotplug
to vendor services which is required by at least some camera
hal implementations.

Test: VtsFwkDisplayServiceV1_0TargetTest
Test: no denials
Bug: 38311538
Change-Id: I64f0321e2832facf987057f0d48940e269d8e2d9

private/hwservice_contexts

+android.frameworks.displayservice::IDisplayService              u:object_r:fwk_display_hwservice:s0
 android.frameworks.schedulerservice::ISchedulingPolicyService   u:object_r:fwk_scheduler_hwservice:s0
 android.frameworks.sensorservice::ISensorManager                u:object_r:fwk_sensor_hwservice:s0
 android.hardware.audio.effect::IEffectsFactory                  u:object_r:hal_audio_hwservice:s0

private/surfaceflinger.te

@@ -6,6 +6,7 @@ type surfaceflinger_exec, exec_type, file_type;
 init_daemon_domain(surfaceflinger)
 
 typeattribute surfaceflinger mlstrustedsubject;
+typeattribute surfaceflinger display_service_server;
 
 read_runtime_log_tags(surfaceflinger)
 

public/attributes

@@ -272,4 +272,5 @@ attribute hal_wifi_supplicant_server;
 # from one core domain to another, without having to update the vendor image
 # which contains clients of this service.
 
+attribute display_service_server;
 attribute wifi_keystore_service_server;

public/display_service_server.te

+add_hwservice(display_service_server, fwk_display_hwservice)

public/hwservice.te

 type default_android_hwservice, hwservice_manager_type;
+type fwk_display_hwservice, hwservice_manager_type, coredomain_hwservice;
 type fwk_scheduler_hwservice, hwservice_manager_type, coredomain_hwservice;
 type fwk_sensor_hwservice, hwservice_manager_type, coredomain_hwservice;
 type hal_audio_hwservice, hwservice_manager_type;