build: create dev-infra-private npm package (#35862)

Creates the scaffolding for an @angular/dev-infra-private package
which will not be published to npm but will be pushed to
https://github.com/angular/dev-infra-private-builds repo for each
commit to master.

The contents of this npm package will then be depended on via
package.json dependency for angular/angular angular/angular-cli and
angular/components.

PR Close #35862

scripts/build/dev-infra-builder.js

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+'use strict';
+
+const {chmod, cp, mkdir, rm} = require('shelljs');
+const {baseDir, bazelBin, bazelCmd, exec, scriptPath} = require('./package-builder');
+
+/**
+ * Build the `@angular/dev-infra-private` npm package and copies it to `dist/packages-dist`.
+ */
+function buildDevInfraPackage() {
+  console.info('##############################');
+  console.info(`${scriptPath}:`);
+  console.info('  Building @angular/dev-infra-private npm package');
+  console.info('##############################');
+  exec(`${bazelCmd} build //dev-infra:npm_package`);
+
+  const buildOutputDir = `${bazelBin}/dev-infra/npm_package`;
+  const distTargetDir = `${baseDir}/dist/packages-dist/dev-infra-private`;
+
+  console.info(`# Copy artifacts to ${distTargetDir}`);
+  mkdir('-p', distTargetDir);
+  rm('-rf', distTargetDir);
+  cp('-R', buildOutputDir, distTargetDir);
+  chmod('-R', 'u+w', distTargetDir);
+
+  console.info('');
+}
+
+module.exports = {
+  buildDevInfraPackage
+};