Re-submit "Add genrule for the current sdk proto"

This reverts commit e15e6483f6,
but adds embedded_launcher: true, as well as a copy of sdk.proto
as a workaround.

...which should hopefully fix the python3-issues.

Test: m cur_sdkinfo
Change-Id: I58aff4e175bd44372e9e03e67439085f08ccdc5e

apex/sdkext/Android.bp

@@ -19,6 +19,7 @@ apex {
     java_libs: [ "framework-sdkext" ],
     prebuilts: [
       "com.android.sdkext.ldconfig",
+      "cur_sdkinfo",
       "derive_sdk.rc",
     ],
     key: "com.android.sdkext.key",
@@ -42,3 +43,33 @@ prebuilt_etc {
     filename: "ld.config.txt",
     installable: false,
 }
+
+python_binary_host {
+    name: "gen_sdkinfo",
+    srcs: [
+        "sdk.proto",
+        "gen_sdkinfo.py",
+    ],
+    proto: {
+        canonical_path_from_root: false,
+    },
+    version: {
+        py3: {
+            embedded_launcher: true,
+        },
+    },
+}
+
+gensrcs {
+    name: "cur_sdkinfo_src",
+    srcs: [""],
+    tools: [ "gen_sdkinfo" ],
+    cmd: "$(location) -v 0 -o $(out)",
+}
+
+prebuilt_etc {
+    name: "cur_sdkinfo",
+    src: ":cur_sdkinfo_src",
+    filename: "sdkinfo.binarypb",
+    installable: false,
+}

apex/sdkext/gen_sdkinfo.py

@@ -0,0 +1,19 @@
+import sdk_pb2
+import sys
+
+if __name__ == '__main__':
+  argv = sys.argv[1:]
+  if not len(argv) == 4 or sorted([argv[0], argv[2]]) != ['-o', '-v']:
+    print('usage: gen_sdkinfo -v <version> -o <output-file>')
+    sys.exit(1)
+
+  for i in range(len(argv)):
+    if sys.argv[i] == '-o':
+      filename = sys.argv[i+1]
+    if sys.argv[i] == '-v':
+      version = int(sys.argv[i+1])
+
+  proto = sdk_pb2.SdkVersion()
+  proto.version = version
+  with open(filename, 'wb') as f:
+    f.write(proto.SerializeToString())

apex/sdkext/sdk.proto

@@ -0,0 +1,25 @@
+/*
+ * Copyright (C) 2019 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 = "proto3";
+package com.android.sdkext.proto;
+
+option java_outer_classname = "SdkProto";
+option optimize_for = LITE_RUNTIME;
+
+message SdkVersion {
+  int32 version = 1;
+}