extensions/test/data/web_view/media_access/check/manifest.json

{
  "name": "Platform App Test: <webview> media",
  "manifest_version": 2,
  "description": "Loads a guest which requests media sources, this triggers checking existing permission",
  "version": "1",
  "permissions": [
    "webview"
  ],
  "app": {
    "background": {
      "scripts": ["test.js"]
    }
  }
}