1) everyone forgets to do so (proof: tst_qnetworkaccessmanager_and_qprogressdialog.cpp
forgot too, which led to a valgrind warning, the elapsed timer was never started)
2) setValue(0) makes no sense if the progress dialog goes from 50 to 60,
or any other non-zero minimum value.
Fixed by starting the timer in the constructor (most code doesn't reuse
progress dialogs, so this fixes the most common case), and by also starting
the timer when calling setValue(minimum()) for well-behaved dialogs.
setValue(0) special case kept for compatibility.
Task-number: QTBUG-17427
Task-number: QTBUG-25316
[ChangeLog][Important Behavior Changes][QProgressDialog] The timer for estimating
the duration of the progress dialog is now started in the constructor and in
setValue(minimum()), as well as when calling setValue(0), as previously documented.
Done-with: Marc Mutz <marc.mutz@kdab.com>
Change-Id: Ia8f7fc677438749191b99074fc334eab652ea36f
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
3c6f333634