Chrome Version: 65.0.3325.162
OS: macOS 10.13.3

What steps will reproduce the problem?
(1) Load https://datatracker.ietf.org/meeting/agenda/#quic
(2) Under the "Schedule" calendar (not the line-items), click the green "QUIC" session on Monday
(3) Click "Minutes" in that frame, which will attempt to load http://etherpad.tools.ietf.org:9000/p/notes-ietf-101-quic

What is the expected result?
An error message indicating either that
1) It was blocked due to the CSP policy
2) It was blocked due to being mixed content

What happens instead?
An error message indicating that the connection to the server "has been blocked by an extension"

The most likely cause by this is showing the error message for net::ERR_BLOCKED_BY_CLIENT in //components/error_page/common/localized_error