Chrome Version: 64.0.3275.0

Also see: https://bugs.chromium.org/p/chromium/issues/detail?id=787532

Steps To Reproduce:
(1) Run a series of FSP operation that takes longer than 10 seconds each, but finishes about in 15 seconds. Typically this is unzipping multiple files in a zip file by ZIP unpacker, each of which are very large, or packed twice.

User will see "operation taking longer than expected" notification, but it will be dismissed by itself after a while.
As a result, user will see the notification flashing multiple times.
It is not necessarily wrong, but might be unfriendly.