Add boot animation progress system property.

Test: m
Bug: 175686819
Change-Id: I52bcd0b9f94d91e963620278042ba076215143db
diff --git a/private/property_contexts b/private/property_contexts
index ae9e141..6787087 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -818,6 +818,7 @@
 ro.vendor.redirect_socket_calls u:object_r:vendor_socket_hook_prop:s0 exact bool
 
 service.bootanim.exit u:object_r:exported_system_prop:s0 exact int
+service.bootanim.progress u:object_r:exported_system_prop:s0 exact int
 
 sys.init.userspace_reboot.in_progress u:object_r:userspace_reboot_exported_prop:s0 exact bool
 sys.use_memfd                         u:object_r:use_memfd_prop:s0 exact bool