Created attachment 247532 [details]
Registering a custom protocol for "http" causes navigation issues, even if the protocol does nothing (i.e. it always returns NO in canInitWithRequest:)
Steps to reproduce:
1. Open & run the attached sample project
2. Search Google for "getbootstrap"
3. Click on the result that takes you to getbootstrap.com
4. Notice how the page fails to load
5. Right click and show inspector, then go to errors
6. Notice how WebKit tries to load the getbootstrap.com resources from google.com
Basically, the custom protocol somehow causes WebKit to get confused about what its current URL is and how to resolve relative paths.