Protocol Handling Web Platform Test

This test validates that an install application can register URL protocol handlers via a property in the web app manifest. The app should open directly when the 'web+testing' custom-scheme URL is visited.

Manual Test Steps:

1. Install this app.
2. Launch 'web+testing://test-url/'. Instructions will vary by OS.
   • On Windows - open a command prompt, and run "start web+testing://test-url/".
   • On MacOS - open a terminal, and "open web+testing://test-url/".
   • On Linux - open a terminal, and "xgd-open web+testing://test-url/".
3. If your browser prompts you, allow the app to open.
4. The app window that opens should indicate success of this test.