Add SystemMessages protos to Connectivity

This follows the model used for the same protos by the Wifi module in
service-wifi.

SystemMessageProto is used by NetworkNotificationManager to define IDs
for notifications that are also counted in system notification metrics.

Bug: 171860710
Test: m
Change-Id: Iec674913fad9ad59c04249714a08b5a0d8ab0f84

service/Android.bp

@@ -68,6 +68,7 @@ java_library {
         "net-utils-framework-common",
         "netd-client",
         "PlatformProperties",
+        "service-connectivity-protos",
     ],
     apex_available: [
         "//apex_available:platform",
@@ -75,6 +76,21 @@ java_library {
     ],
 }
 
+java_library {
+    name: "service-connectivity-protos",
+    proto: {
+        type: "nano",
+    },
+    srcs: [
+        ":system-messages-proto-src",
+    ],
+    libs: ["libprotobuf-java-nano"],
+    apex_available: [
+        "//apex_available:platform",
+        "com.android.tethering",
+    ],
+}
+
 java_library {
     name: "service-connectivity",
     installable: true,

service/jarjar-rules.txt

@@ -12,3 +12,6 @@ rule android.util.LocalLog* com.android.connectivity.util.LocalLog@1
 # the one in com.android.internal.util
 rule android.util.IndentingPrintWriter* android.connectivity.util.IndentingPrintWriter@1
 rule com.android.internal.util.** com.android.connectivity.util.@1
+
+rule com.android.internal.messages.** com.android.connectivity.messages.@1
+rule com.google.protobuf.** com.android.connectivity.protobuf.@1

service/proto/connectivityproto.proto

@@ -0,0 +1,20 @@
+/*
+ * 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.
+ */
+
+syntax = "proto2";
+
+// Connectivity protos can be created in this directory. Note this file must be included before
+// building system-messages-proto, otherwise it will not build by itself.