Restrict visibility to existing users.

Test: m rust
Change-Id: Ie167fe69b7aa2b0b117ae8eec1a4bcb7677a7a0c
diff --git a/Android.bp b/Android.bp
index 58d983e..adbfd89 100644
--- a/Android.bp
+++ b/Android.bp
@@ -73,6 +73,7 @@
     ],
     product_available: true,
     vendor_available: true,
+    visibility: ["//external/rust/crates/x509-parser"],
 }
 
 rust_test {
diff --git a/cargo_embargo.json b/cargo_embargo.json
index 2ff35b0..2e61903 100644
--- a/cargo_embargo.json
+++ b/cargo_embargo.json
@@ -7,6 +7,11 @@
     "crypto",
     "x509"
   ],
+  "module_visibility": {
+    "liboid_registry": [
+      "//external/rust/crates/x509-parser"
+    ]
+  },
   "package": {
     "oid-registry": {
       "copy_out": true