Do column numbers in violation reports start with 0 or 1?

[antosart]

For the column number of a violation report, it looks like Firefox and Chrome have different counting conventions:
https://wpt.fyi/results/content-security-policy/securitypolicyviolation/blockeduri-eval.html?label=experimental&label=master&aligned

Firefox counts from zero, Chrome counts from one. Which one is the correct one?

[annevk]

There's also #442. It would make sense to me if these matched the global error event, but HTML doesn't really define the values for these fields.

cc @domenic