Showing alerts more than once is annoying for the user and basically
useless. We therefore change a bit our strategy:
- if an add-on has behaved correctly for the last 5 minutes, reset our counter of offences;
- don't display alerts for an add-on more than once per 6 hours.
The only exception is if the add-on freezes the browser (i.e. causes
it to stop for more than 5 seconds at a time), in which case we
display the alert regardless of past offences, up to once per 10
minutes.
--HG--
extra : rebase_source : 7c2a875cc0b68eb2e212abdd6a7c1cf8e30c774e
2b6f00954d