917854 - [Session Restore] Start counting saveStateDelayed only once saveState is complete.

Status: NEW

(Firefox :: Session Restore, defect)

Description

[David Teller [:Yoric] - still alive but not very active]

Theoretically, saveStateDelayed() ensures that we only save the state every ~15 seconds at most. However, if the system is busy, the hard drive is slow or the session state is huge, a non-negligible fraction of this time will be used up by the call to saveState() or the off main thread write.

In such cases, we are going to end up spending a large fraction of the time (and the resources available) just processing and saving the state. In extreme cases, we could be spending all our time doing back-to-back saves of the session state, hence rendering Firefox unusable.

I believe that, to avoid this, we should trigger the timer only after saveState() is complete (including the off main thread write).