Add placeholder for types generated from AIDL

Test: None
Bug: 160623310
Change-Id: Ib16003543c416010edf17ee7659033434d70c0f3
diff --git a/keystore2/Android.bp b/keystore2/Android.bp
index 5df94cb..4b031f8 100644
--- a/keystore2/Android.bp
+++ b/keystore2/Android.bp
@@ -25,3 +25,12 @@
     test_suites: ["general-tests"],
     auto_gen_config: true,
 }
+
+// This is a placeholder for the libraries that will be generated from the AIDL specs
+// eventually.
+rust_library {
+    name: "libkeystore_aidl_generated",
+    crate_name: "keystore_aidl_generated",
+
+    srcs: ["src/aidl_generated.rs"],
+}