Revert of IntersectionObserver: use an idle callback to send notifications.

Revert of IntersectionObserver: use an idle callback to send notifications. (patchset #6 id:100001 of https://codereview.chromium.org/1776493002/ )

Reason for revert:
Tests added are leaking, https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/builds/18011

Original issue's description:
> IntersectionObserver: use an idle callback to send notifications.
>
> With this change, the tests can no longer use setTimeout(0) to wait
> for notifications to be delivered.  Instead, use takeRecords() to
> proactively grab notifications right after they are generated
> (typically in a RAF right after a layout change).
>
> BUG=540528
> R=ojan@chromium.org,haraken@chromium.org
>
> Committed: https://crrev.com/2c168f38b5c0e4e50374be4e54c44901c60738a9
> Cr-Commit-Position: refs/heads/master@{#380278}

TBR=ojan@chromium.org,haraken@chromium.org,skyostil@chromium.org,szager@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=540528
Committed: https://crrev.com/57644d439ce9bfee85efedff9f27a31e3e0bd3f5
Cr-Commit-Position: refs/heads/master@{#380375}

[sof, 2016-03-10 08:38:55]

Created Revert of IntersectionObserver: use an idle callback to send
notifications.

[commit-bot: I haz the power, 2016-03-10 08:39:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1780163002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1780163002/1

[commit-bot: I haz the power, 2016-03-10 08:40:35]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-10 08:41:43]

Description was changed from

==========
Revert of IntersectionObserver: use an idle callback to send notifications.
(patchset #6 id:100001 of https://codereview.chromium.org/1776493002/ )

Reason for revert:
Tests added are leaking,
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/b...

Original issue's description:
> IntersectionObserver: use an idle callback to send notifications.
> 
> With this change, the tests can no longer use setTimeout(0) to wait
> for notifications to be delivered.  Instead, use takeRecords() to
> proactively grab notifications right after they are generated
> (typically in a RAF right after a layout change).
> 
> BUG=540528
> R=ojan@chromium.org,haraken@chromium.org
> 
> Committed: https://crrev.com/2c168f38b5c0e4e50374be4e54c44901c60738a9
> Cr-Commit-Position: refs/heads/master@{#380278}

TBR=ojan@chromium.org,haraken@chromium.org,skyostil@chromium.org,szager@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=540528
==========

to

==========
Revert of IntersectionObserver: use an idle callback to send notifications.
(patchset #6 id:100001 of https://codereview.chromium.org/1776493002/ )

Reason for revert:
Tests added are leaking,
https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Linux%20Leak/b...

Original issue's description:
> IntersectionObserver: use an idle callback to send notifications.
>
> With this change, the tests can no longer use setTimeout(0) to wait
> for notifications to be delivered.  Instead, use takeRecords() to
> proactively grab notifications right after they are generated
> (typically in a RAF right after a layout change).
>
> BUG=540528
> R=ojan@chromium.org,haraken@chromium.org
>
> Committed: https://crrev.com/2c168f38b5c0e4e50374be4e54c44901c60738a9
> Cr-Commit-Position: refs/heads/master@{#380278}

TBR=ojan@chromium.org,haraken@chromium.org,skyostil@chromium.org,szager@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=540528

Committed: https://crrev.com/57644d439ce9bfee85efedff9f27a31e3e0bd3f5
Cr-Commit-Position: refs/heads/master@{#380375}
==========

[commit-bot: I haz the power, 2016-03-10 08:41:44]

Patchset 1 (id:??) landed as
https://crrev.com/57644d439ce9bfee85efedff9f27a31e3e0bd3f5
Cr-Commit-Position: refs/heads/master@{#380375}

[szager1, 2016-03-10 08:43:44]

What does this mean?  The leak log is pretty light on details.

[sof, 2016-03-10 09:38:36]

On 2016/03/10 08:43:44, szager1 wrote:
> What does this mean?  The leak log is pretty light on details.

A document is being indirectly kept alive from a posted idle callback on
shutdown, I'm guessing.

Run layout tests with --enable-leak-detection to reproduce & debug.

[haraken, 2016-03-10 10:09:13]

LGTM

[szager1, 2016-03-12 02:06:15]

On 2016/03/10 09:38:36, sof wrote:
> On 2016/03/10 08:43:44, szager1 wrote:
> > What does this mean?  The leak log is pretty light on details.
> 
> A document is being indirectly kept alive from a posted idle callback on
> shutdown, I'm guessing.
> 
> Run layout tests with --enable-leak-detection to reproduce & debug.

Running with --enable-leak-detection gives me:

[1/1] inters...ot.html failed unexpectedly (leak detected:
({"numberOfLiveActiveDOMObjects":[2,3]}))

I modified the test code to pause long enough to let the idle task complete
before finishing, and with some printf debugging, I have verified that there's
no unfinished IntersectionObserverController idle task at shutdown.

So I'm at a loss.  How do I debug this further?