592751 - Open a blank tab when the device is idle, to force the active tab into the background

Status: RESOLVED INVALID

(Firefox for Android Graveyard :: General, defect)

Description

[Alon Zakai (:azakai)]

We do less work on certain things when in a background tab - for example, we do not draw changes, and we should be pausing animation timers as well. So, if Fennec would browse to a new tab with about:blank when the device is idle (or maybe shuts off the screen), we could save power that way. We'd remove the about:blank tab when we become active again.

(In theory we could browse all open tabs to about:blank - forcing them into the bfcache - and save even more (timeouts, for example), but the cost would be

* Time to reload from bfcache
* Losing the forward history
* Possibly losing DOM info if the bfcache does not preserve everything exactly
* Maybe mess up stuff with timeouts that the user expected to continue running
)

Comment 1

[Alon Zakai (:azakai)]

I have been told the new tab would show up in the history. So that's not good.

We may consider using the nsDocument API for marking a tab as active/inactive directly - marking all tabs as inactive when the display is idle, say.

Comment 2

[Doug Turner (:dougt)]

alon, can you work with UX to talk through the trade offs here.  By doing what you are suggesting means that background tabs will not run JS... and that means sites f.e. that play music will stop playing.  not sure what the right trade offs are off hand.

Comment 3

[Doug Turner (:dougt)]

not blocking fennec without a clear path as to what to do.

Comment 4

[Alon Zakai (:azakai)]

To be honest the more I think about this the less I like the idea. I'm not sure I am still in favor of it.

Comment 5

[Alon Zakai (:azakai)]

I retract this idea.