Move hal_light to attribute.

HAL policy defines how the platform and a given HAL interact, but not how the
HAL is implemented.  This policy should be represented as an attribute that all
processes implementing the HAL can include.

Bug: 32123421
Test: Builds.
Change-Id: I17e5612c0835773c28e14f09e2ce7bdc3f210c15

private/file_contexts

@@ -227,7 +227,7 @@
 /system/bin/hw/android\.hardware\.boot@1\.0-service           u:object_r:hal_boot_exec:s0
 /system/bin/hw/android\.hardware\.graphics\.allocator@2\.0-service   u:object_r:hal_graphics_allocator_exec:s0
 /system/bin/hw/android\.hardware\.graphics\.composer@2\.1-service    u:object_r:hal_graphics_composer_exec:s0
-/system/bin/hw/android\.hardware\.light@2\.0-service          u:object_r:hal_light_exec:s0
+/system/bin/hw/android\.hardware\.light@2\.0-service          u:object_r:hal_light_default_exec:s0
 /system/bin/hw/android\.hardware\.memtrack@1\.0-service       u:object_r:hal_memtrack_exec:s0
 /system/bin/hw/android\.hardware\.nfc@1\.0-service            u:object_r:hal_nfc_exec:s0
 /system/bin/hw/android\.hardware\.power@1\.0-service          u:object_r:hal_power_exec:s0

private/hal_light.te

@@ -1,2 +0,0 @@
-# may be started by init
-init_daemon_domain(hal_light)

private/hal_light_default.te

@@ -0,0 +1,5 @@
+type hal_light_default, hal_light, domain;
+type hal_light_default_exec, exec_type, file_type;
+
+# may be started by init
+init_daemon_domain(hal_light_default)

public/attributes

@@ -113,3 +113,6 @@ attribute boot_control_hal;
 # postinstall. This includes the background daemon and the sideload tool from
 # recovery for A/B devices.
 attribute update_engine_common;
+
+# HALs
+attribute hal_light;

public/hal_light.te

@@ -1,7 +1,3 @@
-# light subsystem
-type hal_light, domain;
-type hal_light_exec, exec_type, file_type;
-
 # hwbinder access
 hwbinder_use(hal_light)