[heap] Cancel tasks before tearing down the heap.

[heap] Cancel tasks before tearing down the heap.

BUG=chromium:654343
Committed: https://crrev.com/9365463d6f1fc11b2369fff63ca0ac825c61eae4
Cr-Commit-Position: refs/heads/master@{#40272}

[ulan, 2016-10-13 11:57:57]

ulan@chromium.org changed reviewers:
+ mlippautz@chromium.org

[ulan, 2016-10-13 11:57:57]

ptal

[Michael Lippautz, 2016-10-13 13:32:35]

lgtm

lgtm

[ulan, 2016-10-13 13:35:00]

The CQ bit was checked by ulan@chromium.org

[commit-bot: I haz the power, 2016-10-13 13:35:09]

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, 2016-10-13 14:35:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-10-13 14:35:21]

Description was changed from

==========
[heap] Cancel tasks before tearing down the heap.

BUG=chromium:654343
==========

to

==========
[heap] Cancel tasks before tearing down the heap.

BUG=chromium:654343

Committed: https://crrev.com/9365463d6f1fc11b2369fff63ca0ac825c61eae4
Cr-Commit-Position: refs/heads/master@{#40272}
==========

[commit-bot: I haz the power, 2016-10-13 14:35:22]

Patchset 2 (id:??) landed as
https://crrev.com/9365463d6f1fc11b2369fff63ca0ac825c61eae4
Cr-Commit-Position: refs/heads/master@{#40272}

[ulan, 2016-10-13 16:16:14]

A revert of this CL (patchset #2 id:20001) has been created in
https://codereview.chromium.org/2414073002/ by ulan@chromium.org.

The reason for reverting is: Timeout on gc stress bot..