Add downloaded file policy.

Change-Id: I6f68323cddcf9e13b2a730b8d6b8730587fb4366
diff --git a/file_contexts b/file_contexts
index ccbb99a..3d885b1 100644
--- a/file_contexts
+++ b/file_contexts
@@ -186,6 +186,8 @@
 /data/data/com.android.settings/files/wallpaper	u:object_r:wallpaper_file:s0
 # Wallpaper file for other users
 /data/system/users/[0-9]+/wallpaper		u:object_r:wallpaper_file:s0
+# Downloaded files
+/data/data/com.android.providers.downloads/cache u:object_r:download_file:s0
 #############################
 # efs files
 #