The "PASS" return type should pass on control to the next extension to determine the proxy configuration. We should fall back to "DIRECT" if there aren't any other extensions to pass control to. For more information, see the proxy API design document: https://docs.google.com/document/d/1W45o5X2bFRPrTaQDFp9IzTJ8njCVfEgyENS7i2owaUI/edit?usp=sharing
How is this fixed/resolved? Is it already supported by the implementation in bug #1295807?