fix(material/schematics): add schematic to rename tokens

Author: andrewseguin

src/material/schematics/ng-update/index.ts

@@ -12,6 +12,7 @@ import {
   NullableDevkitMigration,
   TargetVersion,
 } from '@angular/cdk/schematics';
+import {TokenVariableMigration} from './migrations/rename-mdc-tokens';
 
 import {materialUpgradeData} from './upgrade-data';
 import {MatCoreMigration} from './migrations/mat-core-removal';
@@ -20,6 +21,7 @@ import {ExplicitSystemVariablePrefixMigration} from './migrations/explicit-syste
 const materialMigrations: NullableDevkitMigration[] = [
   MatCoreMigration,
   ExplicitSystemVariablePrefixMigration,
+  TokenVariableMigration,
 ];
 
 /** Entry point for the migration schematics with target of Angular Material v19 */

src/material/schematics/ng-update/migrations/rename-mdc-tokens.ts

@@ -0,0 +1,19 @@
+/**
+ * @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.dev/license
+ */
+
+import * as postcss from 'postcss';
+import * as scss from 'postcss-scss';
+import {DevkitContext, Migration, ResolvedResource, UpgradeData} from '@angular/cdk/schematics';
+
+export class TokenVariableMigration extends Migration<UpgradeData, DevkitContext> {
+  override enabled = true;
+
+  override visitStylesheet(stylesheet: ResolvedResource): void {
+    // Do some migration
+  }
+}

src/material/schematics/ng-update/test-cases/rename-mdc-tokens.spec.ts

@@ -0,0 +1,43 @@
+import {UnitTestTree} from '@angular-devkit/schematics/testing';
+import {createTestCaseSetup} from '@angular/cdk/schematics/testing';
+import {MIGRATION_PATH} from '../../paths';
+
+const THEME_FILE_PATH = '/projects/cdk-testing/src/theme.scss';
+
+describe('v20 rename tokens migration', () => {
+  let tree: UnitTestTree;
+  let writeFile: (filename: string, content: string) => void;
+  let runMigration: () => Promise<unknown>;
+
+  function stripWhitespace(content: string): string {
+    return content.replace(/\s/g, '');
+  }
+
+  beforeEach(async () => {
+    const testSetup = await createTestCaseSetup('migration-v20', MIGRATION_PATH, []);
+    tree = testSetup.appTree;
+    writeFile = testSetup.writeFile;
+    runMigration = testSetup.runFixers;
+  });
+
+  it('should rename mdc tokens to mat', async () => {
+    writeFile(
+      THEME_FILE_PATH,
+      `
+        html {
+          --mdc-icon-button-icon-size: 24px;
+        }
+      `,
+    );
+
+    await runMigration();
+
+    expect(stripWhitespace(tree.readText(THEME_FILE_PATH))).toBe(
+      stripWhitespace(`
+        html {
+          --mat-icon-button-icon-size: 24px;
+        }
+    `),
+    );
+  });
+});