Export rpc_unstable header

It'll be used by microdroid payload.

Test: build
Change-Id: I6eaccb55f291a7426ee047bbf6f1f2d211b5b94d
diff --git a/libs/binder/rust/Android.bp b/libs/binder/rust/Android.bp
index fe2da18..d9d7caf 100644
--- a/libs/binder/rust/Android.bp
+++ b/libs/binder/rust/Android.bp
@@ -109,7 +109,7 @@
 // TODO(b/184872979): remove once the Rust API is created.
 rust_bindgen {
     name: "libbinder_rpc_unstable_bindgen",
-    wrapper_src: "src/binder_rpc_unstable.hpp",
+    wrapper_src: ":libbinder_rpc_unstable_header",
     crate_name: "binder_rpc_unstable_bindgen",
     source_stem: "bindings",
     shared_libs: [
diff --git a/libs/binder/rust/src/binder_rpc_unstable.hpp b/libs/binder/rust/src/binder_rpc_unstable.hpp
deleted file mode 100644
index 7932d0f..0000000
--- a/libs/binder/rust/src/binder_rpc_unstable.hpp
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
- * Copyright (C) 2021 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#pragma once
-
-extern "C" {
-
-struct AIBinder;
-
-bool RunRpcServer(AIBinder* service, unsigned int port);
-AIBinder* RpcClient(unsigned int cid, unsigned int port);
-
-}