Hello,
the documentation for the chrome.webNavigation.onCommitted event[1] in the webNavigation API mentions that the details.transitionType can have one of the following values:
"link", "typed", "auto_bookmark", "auto_subframe", "manual_subframe", "generated","start_page", "form_submit", "reload", "keyword", or "keyword_generated"
There is "auto_bookmark", "auto_subframe" but no "auto_toplevel". However, in the chromium code there is a PAGE_TRANSITION_AUTO_TOPLEVEL value. Is it just an omission in the extensions API or is it guaranteed that extensions will never receive any chrome.webNavigation.onCommitted events for "auto_toplevel" transitions?
[1]
http://developer.chrome.com/extensions/webNavigation.html#event-onCommitted