Updated the files.

my-app/node_modules/@angular-devkit/schematics/tools/file-system-engine-host.d.ts

@@ -0,0 +1,28 @@
+/**
+ * @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 { Observable } from 'rxjs';
+import { RuleFactory, TaskExecutor } from '../src';
+import { FileSystemCollectionDesc, FileSystemSchematicDesc } from './description';
+import { FileSystemEngineHostBase } from './file-system-engine-host-base';
+/**
+ * A simple EngineHost that uses a root with one directory per collection inside of it. The
+ * collection declaration follows the same rules as the regular FileSystemEngineHostBase.
+ */
+export declare class FileSystemEngineHost extends FileSystemEngineHostBase {
+    protected _root: string;
+    constructor(_root: string);
+    protected _resolveCollectionPath(name: string): string;
+    protected _resolveReferenceString(refString: string, parentPath: string): {
+        ref: RuleFactory<{}>;
+        path: string;
+    } | null;
+    protected _transformCollectionDescription(name: string, desc: Partial<FileSystemCollectionDesc>): FileSystemCollectionDesc;
+    protected _transformSchematicDescription(name: string, _collection: FileSystemCollectionDesc, desc: Partial<FileSystemSchematicDesc>): FileSystemSchematicDesc;
+    hasTaskExecutor(name: string): boolean;
+    createTaskExecutor(name: string): Observable<TaskExecutor>;
+}