Try not to let the AUHAL driver get stuck sending silence.

Try not to let the AUHAL driver get stuck sending silence.

It seems that when waking from sleep we may miss device change
notifications and end up in a perpetually silent state.

Try to avoid this by posting a task if we get into this state.  Only
do this once.  AudioManagerMac will ignore the request if no change
has taken place.

BUG=160920, 249830
TEST=no crashes. audio plays, device changes work.

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=207786

[Chris Rogers, 2013-06-20 19:13:19]

This is kind of ugly.  Have you been able to confirm it fixes the
wake-from-sleep issue in particular, or is it just a guess?

https://codereview.chromium.org/17463009/diff/2001/media/audio/mac/audio_auha...
File media/audio/mac/audio_auhal_mac.cc (right):

https://codereview.chromium.org/17463009/diff/2001/media/audio/mac/audio_auha...
media/audio/mac/audio_auhal_mac.cc:217: // We should really be using TryPostTask
here since we don't want to lock,
This codepath is never happening in normal steady-state rendering, right?  It's
just at the end?
If so, then the tryLock() is probably not that important.  If this codepath is
part of normal steady-state rendering then it's very important.

[DaleCurtis, 2013-06-20 19:25:29]

Guess so far, haven't been able to repro so far on my laptop.

https://codereview.chromium.org/17463009/diff/2001/media/audio/mac/audio_auha...
File media/audio/mac/audio_auhal_mac.cc (right):

https://codereview.chromium.org/17463009/diff/2001/media/audio/mac/audio_auha...
media/audio/mac/audio_auhal_mac.cc:217: // We should really be using TryPostTask
here since we don't want to lock,
On 2013/06/20 19:13:19, Chris Rogers wrote:
> This codepath is never happening in normal steady-state rendering, right? 
It's
> just at the end?
> If so, then the tryLock() is probably not that important.  If this codepath is
> part of normal steady-state rendering then it's very important.

Correct, it's a one time thing too, so you're right TryLock is probably not
necessary here.  I'll remove the comment.

[Chris Rogers, 2013-06-20 19:27:29]

ok, lgtm since you want to try this out.  But if it doesn't solve the problem
out in the field, please remove later on.

[commit-bot: I haz the power, 2013-06-20 19:41:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/dalecurtis@chromium.org/17463009/9001

[commit-bot: I haz the power, 2013-06-21 10:14:56]

Change committed as 207786