Stop calling Persistent::uninitialize after blink::shutdown is called.

Stop calling Persistent::uninitialize after blink::shutdown is called.

This CL adds a short-term hack to prevent use-after-frees during a shutdown sequence.
Currently the following scenario can happen:

1) blink::shutdown() frees the underlying storage for persistent nodes.
2) ~MessageLoop() destructs some Chromium-side objects that hold Persistent.
It touches the underlying storage and crashes.

In middle term, we should entirely remove the shutdown sequence and get rid of the hack.

BUG=653688
Committed: https://crrev.com/10d68110da927986332bd753b17c08db0feac1c8
Cr-Commit-Position: refs/heads/master@{#425620}

[haraken, 2016-10-17 01:35:03]

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

[haraken, 2016-10-17 01:35:04]

PTAL

[keishi, 2016-10-17 01:39:40]

LGTM

[haraken, 2016-10-17 01:40:01]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2016-10-17 01:40:08]

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, 2016-10-17 05:24:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-17 05:26:42]

Description was changed from

==========
Stop calling Persistent::uninitialize after blink::shutdown is called.

This CL adds a short-term hack to prevent use-after-frees during a shutdown
sequence.
Currently the following scenario can happen:

1) blink::shutdown() frees the underlying storage for persistent nodes.
2) ~MessageLoop() destructs some Chromium-side objects that hold Persistent.
It touches the underlying storage and crashes.

In middle term, we should entirely remove the shutdown sequence and get rid of
the hack.

BUG=653688
==========

to

==========
Stop calling Persistent::uninitialize after blink::shutdown is called.

This CL adds a short-term hack to prevent use-after-frees during a shutdown
sequence.
Currently the following scenario can happen:

1) blink::shutdown() frees the underlying storage for persistent nodes.
2) ~MessageLoop() destructs some Chromium-side objects that hold Persistent.
It touches the underlying storage and crashes.

In middle term, we should entirely remove the shutdown sequence and get rid of
the hack.

BUG=653688

Committed: https://crrev.com/10d68110da927986332bd753b17c08db0feac1c8
Cr-Commit-Position: refs/heads/master@{#425620}
==========

[commit-bot: I haz the power, 2016-10-17 05:26:43]

Patchset 1 (id:??) landed as
https://crrev.com/10d68110da927986332bd753b17c08db0feac1c8
Cr-Commit-Position: refs/heads/master@{#425620}