chromium/chrome/test/data/extensions/platform_apps/web_view/common/manifest.json

{
  "name": "Platform App Test: <webview> New Window",
  "manifest_version": 2,
  "description": "Loads a an to run WebViewTest and WebViewInteractive tests.",
  "version": "1",
  /**
   * Careful when adding permissions here.
   * In regular case, you shouldn't require to add more permissions here.
   * If you do, create a separate test app.
   */
  "permissions": [
    "webview"
  ],
  "app": {
    "background": {
      "scripts": ["test.js"]
    }
  }
}