Bootstrap IInputFlingerRust - the Rust component of inputflinger

When inputflinger boots, we create the Rust component of inputflinger,
which we interact with from C++ through the local AIDL interface
IInputFlingerRust.

After we have access to the IInputFlingerRust binder object in C++, all
communication between C++ and Rust can take place purely through AIDL
interfaces.

To initialize the interface, we must first pass a raw pointer to an AIDL
implementation across the language barrier through some other means. In
this CL, we use cxxbridge to bootstrap the local AIDL interface for
IInputFlingerRust.

Bug: 278783893
Test: manual, boot
Change-Id: Ifbd0168ae4fadaa5b357f6064113f1691e6cf5a7
diff --git a/services/inputflinger/aidl/Android.bp b/services/inputflinger/aidl/Android.bp
new file mode 100644
index 0000000..314c433
--- /dev/null
+++ b/services/inputflinger/aidl/Android.bp
@@ -0,0 +1,31 @@
+// Copyright 2023 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.
+
+aidl_interface {
+    name: "com.android.server.inputflinger",
+    srcs: ["**/*.aidl"],
+    unstable: true,
+    host_supported: true,
+    backend: {
+        cpp: {
+            enabled: false,
+        },
+        java: {
+            enabled: false,
+        },
+        rust: {
+            enabled: true,
+        },
+    },
+}
diff --git a/services/inputflinger/aidl/com/android/server/inputflinger/IInputFlingerRust.aidl b/services/inputflinger/aidl/com/android/server/inputflinger/IInputFlingerRust.aidl
new file mode 100644
index 0000000..8e826fd
--- /dev/null
+++ b/services/inputflinger/aidl/com/android/server/inputflinger/IInputFlingerRust.aidl
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2023 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.
+ */
+
+package com.android.server.inputflinger;
+
+/**
+ * A local AIDL interface used as a foreign function interface (ffi) to
+ * communicate with the Rust component of inputflinger.
+ *
+ * NOTE: Since we use this as a local interface, all processing happens on the
+ * calling thread.
+ */
+interface IInputFlingerRust {
+
+   /**
+    * An interface used to get a strong reference to IInputFlingerRust on boot.
+    */
+    interface IInputFlingerRustBootstrapCallback {
+        void onProvideInputFlingerRust(in IInputFlingerRust inputFlingerRust);
+    }
+}