Add getattr access on tmpfs_zygote files for webview_zygote.

webview_zygote inherits tmpfs files from zygote and needs to stat
them after fork.

Bug: 138851227
Test: run walleye_jitzygote config, fork webview_zygote.
Change-Id: I092b942c0426f3f5731536ae9f2f5886a9196d3d
diff --git a/private/webview_zygote.te b/private/webview_zygote.te
index c618253..969ab9c 100644
--- a/private/webview_zygote.te
+++ b/private/webview_zygote.te
@@ -64,8 +64,8 @@
 # Directory listing in /system.
 allow webview_zygote system_file:dir r_dir_perms;
 
-# Read system properties managed by zygote.
-allow webview_zygote zygote_tmpfs:file read;
+# Read and inspect temporary files (like system properties) managed by zygote.
+allow webview_zygote zygote_tmpfs:file { read getattr };
 # Child of zygote.
 allow webview_zygote zygote:fd use;
 allow webview_zygote zygote:process sigchld;