fix(material-date-fns-adapter): error when added through ng add

Currently adding the `@angular/material-date-fns-adapter` module through `ng add` results in an error because it doesn't have an `ng add` schematic. These changes add a blank one so users don't get an error now and so that we can easily add more functionality in the future.

src/material-date-fns-adapter/BUILD.bazel

@@ -39,6 +39,7 @@ ng_web_test_suite(
 ng_package(
     name = "npm_package",
     srcs = ["package.json"],
+    nested_packages = ["//src/material-date-fns-adapter/schematics:npm_package"],
     tags = ["release-package"],
     deps = [":material-date-fns-adapter"],
 )

src/material-date-fns-adapter/package.json

@@ -26,5 +26,6 @@
       "@angular/material-date-fns-adapter"
     ]
   },
+  "schematics": "./schematics/collection.json",
   "sideEffects": false
 }

src/material-date-fns-adapter/schematics/BUILD.bazel

@@ -0,0 +1,34 @@
+load("@build_bazel_rules_nodejs//:index.bzl", "copy_to_bin")
+load("//tools:defaults.bzl", "pkg_npm", "ts_library")
+
+package(default_visibility = ["//visibility:public"])
+
+copy_to_bin(
+    name = "schematics_assets",
+    srcs = glob(["**/*.json"]),
+)
+
+ts_library(
+    name = "schematics",
+    srcs = glob(
+        ["**/*.ts"],
+        exclude = ["**/*.spec.ts"],
+    ),
+    # Schematics can not yet run in ESM module. For now we continue to use CommonJS.
+    # TODO(ESM): remove this once the Angular CLI supports ESM schematics.
+    devmode_module = "commonjs",
+    prodmode_module = "commonjs",
+    deps = [
+        "@npm//@angular-devkit/schematics",
+        "@npm//@types/node",
+    ],
+)
+
+# This package is intended to be combined into the main @angular/material-date-fns-adapter package as a dep.
+pkg_npm(
+    name = "npm_package",
+    deps = [
+        ":schematics",
+        ":schematics_assets",
+    ],
+)

src/material-date-fns-adapter/schematics/collection.json

@@ -0,0 +1,10 @@
+{
+  "$schema": "../node_modules/@angular-devkit/schematics/collection-schema.json",
+  "schematics": {
+    "ng-add": {
+      "description": "Installs the Angular YouTube Player",
+      "factory": "./ng-add/index",
+      "hidden": true
+    }
+  }
+}

src/material-date-fns-adapter/schematics/ng-add/index.ts

@@ -0,0 +1,15 @@
+/**
+ * @license
+ * Copyright Google LLC 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
+ */
+
+import {Rule} from '@angular-devkit/schematics';
+
+export default function (): Rule {
+  // Noop schematic so the CLI doesn't throw if users try to `ng add` this package.
+  // Also allows us to add more functionality in the future.
+  return () => {};
+}

src/material-date-fns-adapter/schematics/package.json

@@ -0,0 +1,3 @@
+{
+  "type": "commonjs"
+}