Create composd skeleton

This has all the scaffolding/boilerplate to create a composd service
which can be started and serve a binder interface, but with no actual
implementation yet.

Bug: 186126194
Test: adb shell cmd -w android.system.composd; service starts.
Change-Id: I2ba91b36628b21210ac901525a93664473ac8460
diff --git a/compos/apex/Android.bp b/compos/apex/Android.bp
index 853b9f4..ada0976 100644
--- a/compos/apex/Android.bp
+++ b/compos/apex/Android.bp
@@ -40,6 +40,7 @@
     binaries: [
         "compos_key_cmd",
         "compos_verify_key",
+        "composd",
         "compsvc",
         "pvm_exec",
     ],
@@ -50,5 +51,13 @@
 
     prebuilts: [
         "CompOSPayloadApp.apk.idsig",
+        "com.android.compos.init.rc",
     ],
 }
+
+prebuilt_etc {
+    name: "com.android.compos.init.rc",
+    src: "composd.rc",
+    filename: "init.rc",
+    installable: false,
+}
diff --git a/compos/apex/composd.rc b/compos/apex/composd.rc
new file mode 100644
index 0000000..099a346
--- /dev/null
+++ b/compos/apex/composd.rc
@@ -0,0 +1,21 @@
+# 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.
+
+service composd /apex/com.android.compos/bin/composd
+    class main
+    user system
+    group system
+    interface aidl android.system.composd
+    disabled
+    oneshot