Simplify ContextLifecycleNotifier's handling of ActiveDOMObjects.

Simplify ContextLifecycleNotifier's handling of ActiveDOMObjects.

No longer keep a separate set of ActiveDOMObject observers, but iterate
over the notifier set instead.

Also adjust the visibility of various helper methods to what they
need to be.

R=haraken
BUG=462949
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=191177

[sof, 2015-03-02 15:49:24]

sigbjornf@opera.com changed reviewers:
+ haraken@chromium.org

[sof, 2015-03-02 15:49:25]

Please take a look.

I had a closer look at hasPendingActivity() usage, and it is limited to some
constrained Worker uses, so the questions I had wrt performance shouldn't be
real.

[haraken, 2015-03-03 04:46:21]

LGTM

(I still think that hasPendingActivity should belong to ScriptWrappable, but
that's a separate discussion. This CL is a clear improvement.)

https://codereview.chromium.org/965393002/diff/20001/Source/core/dom/ContextL...
File Source/core/dom/ContextLifecycleNotifier.h (right):

https://codereview.chromium.org/965393002/diff/20001/Source/core/dom/ContextL...
Source/core/dom/ContextLifecycleNotifier.h:49: unsigned activeDOMObjectCount()
const { return m_activeDOMObjectCount; }

This is used only in window.internals to count the number of media objects. We
should directly count up the number of media objects and remove this method (as
you know, windows.internals.activeDOMObjectCount has been a cause to make test
results of encrypted-media tests flaky, because the number of live
ActiveDOMObjects changes as we move more things to Oilpan).

[sof, 2015-03-03 07:26:18]

https://codereview.chromium.org/965393002/diff/20001/Source/core/dom/ContextL...
File Source/core/dom/ContextLifecycleNotifier.h (right):

https://codereview.chromium.org/965393002/diff/20001/Source/core/dom/ContextL...
Source/core/dom/ContextLifecycleNotifier.h:49: unsigned activeDOMObjectCount()
const { return m_activeDOMObjectCount; }
On 2015/03/03 04:46:21, haraken wrote:
> 
> This is used only in window.internals to count the number of media objects. We
> should directly count up the number of media objects and remove this method
(as
> you know, windows.internals.activeDOMObjectCount has been a cause to make test
> results of encrypted-media tests flaky, because the number of live
> ActiveDOMObjects changes as we move more things to Oilpan).

Agreed, iterating over the set to count them up is preferable as that
testing-internal use is the only one.

Now done.

[sof, 2015-03-03 07:31:06]

The CQ bit was checked by sigbjornf@opera.com

[sof, 2015-03-03 07:31:07]

The patchset sent to the CQ was uploaded after l-g-t-m from haraken@chromium.org
Link to the patchset: https://codereview.chromium.org/965393002/#ps40001 (title:
"manually count the ActiveDOMObjects instead")

[commit-bot: I haz the power, 2015-03-03 07:33:01]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/965393002/40001

[commit-bot: I haz the power, 2015-03-03 08:20:14]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=191177

[hiroshige, 2015-03-05 08:54:09]

This CL causes crash: https://crbug.com/464285
Could you take a look?

[sof, 2015-03-05 09:14:17]

On 2015/03/05 08:54:09, hiroshige wrote:
> This CL causes crash: https://crbug.com/464285
> Could you take a look?

Thanks, will do. I think I see the weakness, but have to locally verify first.