Fixed the memory leak of callback Task in PostPingMessage....

Fixed the memory leak of callback Task in PostPingMessage.
If PostTask to watched thread fails, we will stop monitoring
that thread.

BUG=73915, 73844
TEST=performance testing


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=75838

[ramant (doing other things), 2011-02-23 23:10:29]

Hi Jim and Willam,
  Made the changes Willam suggested to fix the memory leak. Would appreciate if
you could review the changes (will check-in after try bot is successful).

thanks much,
raman

[willchan no longer on Chromium, 2011-02-23 23:39:02]

http://codereview.chromium.org/6575007/diff/1/chrome/browser/metrics/thread_w...
File chrome/browser/metrics/thread_watcher.cc (right):

http://codereview.chromium.org/6575007/diff/1/chrome/browser/metrics/thread_w...
chrome/browser/metrics/thread_watcher.cc:119: DeActivateThreadWatching();
I have not re-read the changelist since the last round of big changes, so you
should get Jim to look at this. In particular, I'm don't know if
DeActivateThreadWatching() is correct here. It probably is, I just don't know
since I forgot how the CL works :)

[ramant (doing other things), 2011-02-23 23:58:05]

On 2011/02/23 23:39:02, willchan wrote:
>
http://codereview.chromium.org/6575007/diff/1/chrome/browser/metrics/thread_w...
> File chrome/browser/metrics/thread_watcher.cc (right):
> 
>
http://codereview.chromium.org/6575007/diff/1/chrome/browser/metrics/thread_w...
> chrome/browser/metrics/thread_watcher.cc:119: DeActivateThreadWatching();
> I have not re-read the changelist since the last round of big changes, so you
> should get Jim to look at this. In particular, I'm don't know if
> DeActivateThreadWatching() is correct here. It probably is, I just don't know
> since I forgot how the CL works :)

:-). If we can't post a ping task to watched thread (which indicates watched
thread's message_loop is not there), then we could consider that watched thread
as dead. So we could stop monitoring it (i.e., don't send it any more ping
messages). jar suggested deactivating it.

When there is user activity, WakeUp doesn't wakeup deactivated thread watchers
(verified we don't have any busy loops). 

many many thanks willchan for your time, 
raman

[jar (doing other things), 2011-02-24 00:11:57]

LGTM