[Extensions] Fix incorrect counting prefs in activity log

[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853
Committed: https://crrev.com/100d164a4403d22bfa238607ebad71331e5032ad
Cr-Commit-Position: refs/heads/master@{#421870}

[Devlin, 2016-09-27 16:55:36]

The CQ bit was checked by rdevlin.cronin@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-27 16:56:00]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-27 17:05:04]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-27 17:05:05]

Dry run: Try jobs failed on following builders:
  chromium_presubmit on master.tryserver.chromium.linux (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[Devlin, 2016-09-27 19:51:51]

The CQ bit was checked by rdevlin.cronin@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-27 19:52:25]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-27 20:41:29]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-27 20:41:30]

Dry run: This issue passed the CQ dry run.

[Devlin, 2016-09-27 21:48:27]

Description was changed from

==========
inprog


scratch

BUG=
==========

to

==========
[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853
==========

[Devlin, 2016-09-27 21:49:19]

rdevlin.cronin@chromium.org changed reviewers:
+ asargent@chromium.org, felt@chromium.org

[Devlin, 2016-09-27 21:49:20]

asargent@ and felt@, mind taking a look?

[asargent_no_longer_on_chrome, 2016-09-27 22:54:07]

lgtm

https://codereview.chromium.org/2372223003/diff/40001/chrome/browser/extensio...
File chrome/browser/extensions/activity_log/activity_log.cc (right):

https://codereview.chromium.org/2372223003/diff/40001/chrome/browser/extensio...
chrome/browser/extensions/activity_log/activity_log.cc:666: 
nit: collapse double-newline to just one

[felt, 2016-09-29 16:55:01]

lgtm

[Devlin, 2016-09-29 17:06:07]

The CQ bit was checked by rdevlin.cronin@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-09-29 17:06:29]

Dry run: CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-29 17:52:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-09-29 17:52:17]

Dry run: This issue passed the CQ dry run.

[Devlin, 2016-09-29 17:59:42]

https://codereview.chromium.org/2372223003/diff/40001/chrome/browser/extensio...
File chrome/browser/extensions/activity_log/activity_log.cc (right):

https://codereview.chromium.org/2372223003/diff/40001/chrome/browser/extensio...
chrome/browser/extensions/activity_log/activity_log.cc:666: 
On 2016/09/27 22:54:07, Antony Sargent wrote:
> nit: collapse double-newline to just one

Whoops, done.

[Devlin, 2016-09-29 17:59:46]

The CQ bit was checked by rdevlin.cronin@chromium.org

[Devlin, 2016-09-29 17:59:47]

The patchset sent to the CQ was uploaded after l-g-t-m from
asargent@chromium.org, felt@chromium.org
Link to the patchset: https://codereview.chromium.org/2372223003/#ps60001
(title: "nit")

[commit-bot: I haz the power, 2016-09-29 18:00:32]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-09-29 18:07:09]

Description was changed from

==========
[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853
==========

to

==========
[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853
==========

[commit-bot: I haz the power, 2016-09-29 18:07:10]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2016-09-29 18:11:12]

Description was changed from

==========
[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853
==========

to

==========
[Extensions] Fix incorrect counting prefs in activity log

The ActivityLog maintains a count of active apps/extensions that are
listening to the API. This is necessary so that events that happen on
startup (potentially before the extension is loaded) are properly
recorded. Unfortunately, there was a bug where this counter was never
properly decremented. Because of this, there are cases where we are
recording activity, but there are no active consumers.

Fix this by separating the concept of cached consumers and seen active
consumers. During startup, we can rely on the cached consumer count, but
once startup is complete, we check whether or not there is actually a
consumer and update the cached count appropriately.

BUG=646853

Committed: https://crrev.com/100d164a4403d22bfa238607ebad71331e5032ad
Cr-Commit-Position: refs/heads/master@{#421870}
==========

[commit-bot: I haz the power, 2016-09-29 18:11:13]

Patchset 4 (id:??) landed as
https://crrev.com/100d164a4403d22bfa238607ebad71331e5032ad
Cr-Commit-Position: refs/heads/master@{#421870}