Add script for building and archiving rustdocs.

Test: OUT_DIR=out DIST_DIR=dist build/soong/scripts/build-rustdocs.sh
Bug: http://b/162741284
Change-Id: Ie94318ed9cc99024a27d414bfecc083b2fa96b57

scripts/build-rustdocs.sh

@@ -0,0 +1,31 @@
+#!/bin/bash -ex
+
+# Copyright 2021 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.
+
+# Builds the platform rustdocs and copies them to the dist directory to provide
+# online docs for each build.
+
+if [ -z "${OUT_DIR}" ]; then
+    echo Must set OUT_DIR
+    exit 1
+fi
+
+source build/envsetup.sh
+m rustdoc
+
+if [ -n "${DIST_DIR}" ]; then
+    mkdir -p ${DIST_DIR}
+    cp -r ${OUT_DIR}/soong/rustdoc $DIST_DIR/rustdoc
+fi