We still have some issues around callback interfaces, and I'm still working on Issue 778580 , however, the confusion about "to be callback function or to be callback interface" is now resolved. I've converted what should be callback functions into callback functions.
The current status is:
EventListener = specially handled (I'll work on this separately.)
NodeFilter = specially handled (I'll work on this separately.)
ScrollStateCallback = callback interface (No spec. Maybe we'll convert this one, too, in future.)
Filesystem API callbacks = callback interface (spec'ed)
SQL (WebDatabase) API callbacks = callback interface (spec'ed)
The rest of callbacks = callback functions
So, I close this issue as Fixed.
Comment 1 by foolip@chromium.org
, Oct 21 2016