Add user manager AIDL.

Bug: 176123105
Test: TBD
Change-Id: Ic3dc177ffe31d3122b1976a3a4c4cfd27d19809f
diff --git a/keystore2/aidl/Android.bp b/keystore2/aidl/Android.bp
index 36cff16..9af5d6a 100644
--- a/keystore2/aidl/Android.bp
+++ b/keystore2/aidl/Android.bp
@@ -105,3 +105,20 @@
         },
     },
 }
+
+aidl_interface {
+    name: "android.security.usermanager",
+    srcs: [ "android/security/usermanager/*.aidl" ],
+    unstable: true,
+    backend: {
+        java: {
+            sdk_version: "module_current",
+        },
+        rust: {
+            enabled: true,
+        },
+        ndk: {
+            enabled: true,
+        }
+    },
+}