Add metrics.proto as host library.

Build libdrm_metrics_protos_full_host
host library for the metrics_dump tool
in vendor/widevine/libwvdrmengine/tools.

bug: 161783052
bug: 170607430

Test: build android image
Test: build metrics_dump tool
Test: Play movies and TV, Netflix
Change-Id: Ice214b46eedfcd2ef034a5edfdced4f2789d296a
diff --git a/drm/libmediadrm/protos/Android.bp b/drm/libmediadrm/protos/Android.bp
new file mode 100644
index 0000000..b26cda4
--- /dev/null
+++ b/drm/libmediadrm/protos/Android.bp
@@ -0,0 +1,38 @@
+// Copyright (C) 2020 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.
+
+// This is the version of the drm metrics configured for protobuf full on host.
+// It is used by the metrics_dump tool.
+
+cc_library_host_shared {
+    name: "libdrm_metrics_protos_full_host",
+    vendor_available: true,
+
+    include_dirs: ["external/protobuf/src"],
+
+    srcs: [
+        "metrics.proto",
+    ],
+
+    proto: {
+        export_proto_headers: true,
+        type: "full",
+    },
+
+    cflags: [
+        // Suppress unused parameter error. This error occurs
+        // when using the map type in a proto definition.
+        "-Wno-unused-parameter",
+    ],
+}