Pending scripts can cause disposed documents to leak.

Pending scripts can cause disposed documents to leak.

The script runner of a document may still be holding pending scripts
when the document is disposed (e.g. due to navigation). The script
runner, and thus the pending scripts, is cleared in the destructor of
the document. However, the pending scripts keep a reference to the
script element they belong to. The script element in turn, keeps a
guard ref to the document, so the document will never be deleted.
Clearing the script runner in dispose clears the pending scripts and
breaks the reference cycle so that document can be deleted.

BUG=534844
R=sigbjornf@opera.com

Committed: https://crrev.com/da753c3cf6f742b968a9b72d27fdc9baaf8d739b
Cr-Commit-Position: refs/heads/master@{#350664}

[jb, 2015-09-24 12:42:08]

New post blink merge CL of 1358583005. PTAL.

[sof, 2015-09-24 19:52:00]

The CQ bit was checked by sigbjornf@opera.com

[sof, 2015-09-24 19:52:01]

lgtm

[commit-bot: I haz the power, 2015-09-24 19:53:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1368623003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1368623003/1

[commit-bot: I haz the power, 2015-09-24 21:14:27]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-24 21:15:31]

Patchset 1 (id:??) landed as
https://crrev.com/da753c3cf6f742b968a9b72d27fdc9baaf8d739b
Cr-Commit-Position: refs/heads/master@{#350664}