chromium/chrome/test/data/extensions/platform_apps/web_view/filesystem/shared_worker/single/manifest.json

{
  "name": "Platform App Test: <webview> filesystem",
  "manifest_version": 2,
  "description": "Loads a guest which requests filesystem",
  "version": "1",
  "permissions": [
    "webview"
  ],
  "webview": {
    "partitions": [
    {
      "name": "a",
      "accessible_resources": ["*"]
    }
    ]
  },
  "app": {
    "background": {
      "scripts": ["test.js"]
    }
  }
}