Add Code Metadata rule to soong/testing.

This Cl adds a new rule to Soong to generate code ownership metadata. Also, this CL adds a provider in the Java SDK library to provide generated source files to the Code_metadata rule. Will add providers to other libraries in the future changes.

Bug: 296873595
Change-Id: Ic2e43aa9b161231fea4416d1f0d36b778361d7c5

testing/code_metadata_proto/Android.bp

@@ -0,0 +1,29 @@
+// Copyright 2022 Google Inc. All rights reserved.
+//
+// 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 {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+bootstrap_go_package {
+    name: "soong-testing-code_metadata_proto",
+    pkgPath: "android/soong/testing/code_metadata_proto",
+    deps: [
+            "golang-protobuf-reflect-protoreflect",
+            "golang-protobuf-runtime-protoimpl",
+        ],
+    srcs: [
+        "code_metadata.pb.go",
+    ],
+}