Add blur sysprop to sepolicy

Bug: 170378891
Test: m
Change-Id: I6876e3bfe9dfdf066bfa54334555fdab5b3598d5
diff --git a/private/property_contexts b/private/property_contexts
index 8778016..7d99a24 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -979,6 +979,7 @@
 ro.surface_flinger.set_touch_timer_ms                     u:object_r:surfaceflinger_prop:s0 exact int
 ro.surface_flinger.set_display_power_timer_ms             u:object_r:surfaceflinger_prop:s0 exact int
 ro.surface_flinger.support_kernel_idle_timer              u:object_r:surfaceflinger_prop:s0 exact bool
+ro.surface_flinger.supports_background_blur               u:object_r:surfaceflinger_prop:s0 exact bool
 ro.surface_flinger.use_smart_90_for_video                 u:object_r:surfaceflinger_prop:s0 exact bool
 ro.surface_flinger.use_content_detection_for_refresh_rate u:object_r:surfaceflinger_prop:s0 exact bool
 ro.surface_flinger.color_space_agnostic_dataspace         u:object_r:surfaceflinger_prop:s0 exact int