Fix HTMLDocumentParser::stopBackgroundParser crash

Fix HTMLDocumentParser::stopBackgroundParser crash

HTMLDocumentParser::stopBackgroundParser was getting called from
HTMLDocumentParser::~HTMLDocumentParser, this is a problem because it
assumes document() is valid.  That's not always the case since both
HTMLDocumentParser and Document are on the oilpan heap and it's not
allowed to dereference an object like that in the destructor.

As a workaround I've added a pre-finalizer.  This fixes the crash
described in the bug.

BUG=634244
Committed: https://crrev.com/61c5d52a6f5366abfec4474bec4b0dd5965abf22
Cr-Commit-Position: refs/heads/master@{#409806}

[alex clarke (OOO till 29th), 2016-08-04 14:15:46]

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

[alex clarke (OOO till 29th), 2016-08-04 14:15:57]

alexclarke@chromium.org changed reviewers:
+ haraken@chromium.org

[commit-bot: I haz the power, 2016-08-04 14:16:14]

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, 2016-08-04 14:55:45]

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

[commit-bot: I haz the power, 2016-08-04 14:55:46]

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

[alex clarke (OOO till 29th), 2016-08-04 14:58:05]

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

[commit-bot: I haz the power, 2016-08-04 14:58:32]

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

[haraken, 2016-08-04 15:35:07]

LGTM

[alex clarke (OOO till 29th), 2016-08-04 15:52:14]

The CQ bit was unchecked by alexclarke@chromium.org

[alex clarke (OOO till 29th), 2016-08-04 15:52:16]

The CQ bit was checked by alexclarke@chromium.org

[commit-bot: I haz the power, 2016-08-04 15:52:35]

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, 2016-08-04 16:36:29]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-04 16:38:43]

Description was changed from

==========
Fix HTMLDocumentParser::stopBackgroundParser crash

HTMLDocumentParser::stopBackgroundParser was getting called from
HTMLDocumentParser::~HTMLDocumentParser, this is a problem because it
assumes document() is valid.  That's not always the case since both
HTMLDocumentParser and Document are on the oilpan heap and it's not
allowed to dereference an object like that in the destructor.

As a workaround I've added a pre-finalizer.  This fixes the crash
described in the bug.

BUG=634244
==========

to

==========
Fix HTMLDocumentParser::stopBackgroundParser crash

HTMLDocumentParser::stopBackgroundParser was getting called from
HTMLDocumentParser::~HTMLDocumentParser, this is a problem because it
assumes document() is valid.  That's not always the case since both
HTMLDocumentParser and Document are on the oilpan heap and it's not
allowed to dereference an object like that in the destructor.

As a workaround I've added a pre-finalizer.  This fixes the crash
described in the bug.

BUG=634244

Committed: https://crrev.com/61c5d52a6f5366abfec4474bec4b0dd5965abf22
Cr-Commit-Position: refs/heads/master@{#409806}
==========

[commit-bot: I haz the power, 2016-08-04 16:38:44]

Patchset 1 (id:??) landed as
https://crrev.com/61c5d52a6f5366abfec4474bec4b0dd5965abf22
Cr-Commit-Position: refs/heads/master@{#409806}

[kouhei (in TOK), 2016-08-05 05:49:29]

kouhei@chromium.org changed reviewers:
+ kouhei@chromium.org

[kouhei (in TOK), 2016-08-05 05:49:29]

lgtm