feat(ivy): add injectable-pipe schematic (#29847)

Adds a schematic that will annotate all `Pipe` classes with `Injectable` so that they can be injected.

This PR resolves FW-1228.

PR Close #29847

packages/core/schematics/migrations/injectable-pipe/util.ts

@@ -0,0 +1,47 @@
+/**
+ * @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
+ */
+
+import * as ts from 'typescript';
+
+/** Name of the Injectable decorator. */
+export const INJECTABLE_DECORATOR_NAME = 'Injectable';
+
+/**
+ * Adds a named import to an import declaration node.
+ * @param node Node to which to add the import.
+ * @param importName Name of the import that should be added.
+ */
+export function addNamedImport(node: ts.ImportDeclaration, importName: string) {
+  const namedImports = getNamedImports(node);
+
+  if (namedImports && ts.isNamedImports(namedImports)) {
+    const elements = namedImports.elements;
+    const isAlreadyImported = elements.some(element => element.name.text === importName);
+
+    if (!isAlreadyImported) {
+      // If there are named imports, there will be an import clause as well.
+      const importClause = node.importClause !;
+      const newImportClause = ts.createNamedImports(
+          [...elements, ts.createImportSpecifier(undefined, ts.createIdentifier(importName))]);
+
+      return ts.updateImportDeclaration(
+          node, node.decorators, node.modifiers,
+          ts.updateImportClause(importClause, importClause.name, newImportClause),
+          node.moduleSpecifier);
+    }
+  }
+
+  return node;
+}
+
+/** Gets the named imports node from an import declaration. */
+export function getNamedImports(node: ts.ImportDeclaration): ts.NamedImports|null {
+  const importClause = node.importClause;
+  const namedImports = importClause && importClause.namedBindings;
+  return (namedImports && ts.isNamedImports(namedImports)) ? namedImports : null;
+}