Fix crash in Mac ASAN RenderWidgetResizeHelper

Fix crash in Mac ASAN RenderWidgetResizeHelper

It is possible for the TaskRunner to which the tasks were posted
to be destroyed before the RenderWidgetResizeHelper is destroyed.
Make sure that RenderWidgetResizeHelper is robust to this by having
tasks remove themselves from RenderWidgetResizeHelper's queue
when they are destroyed.

BUG=394775
TBR=sky@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=284224

[ccameron, 2014-07-18 18:04:16]

This re-enables the test that was failing. The symbolized stacks from ASAN
explained what was going wrong.

[groby-ooo-7-16, 2014-07-18 18:22:47]

LGTM

https://codereview.chromium.org/399213003/diff/40001/content/browser/renderer...
File content/browser/renderer_host/render_widget_resize_helper.cc (right):

https://codereview.chromium.org/399213003/diff/40001/content/browser/renderer...
content/browser/renderer_host/render_widget_resize_helper.cc:149: task->helper_
= NULL;
task->InvalidateHelper() instead?

[ccameron, 2014-07-18 18:40:27]

Thanks!

https://codereview.chromium.org/399213003/diff/40001/content/browser/renderer...
File content/browser/renderer_host/render_widget_resize_helper.cc (right):

https://codereview.chromium.org/399213003/diff/40001/content/browser/renderer...
content/browser/renderer_host/render_widget_resize_helper.cc:149: task->helper_
= NULL;
On 2014/07/18 18:22:47, groby wrote:
> task->InvalidateHelper() instead?

Yup (no goma on the bus => trybots faster to compile than my machine :/ )

[ccameron, 2014-07-18 18:43:14]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2014-07-18 18:44:51]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ccameron@chromium.org/399213003/60001

[commit-bot: I haz the power, 2014-07-18 21:48:50]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[commit-bot: I haz the power, 2014-07-18 21:58:50]

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

[commit-bot: I haz the power, 2014-07-18 21:58:50]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/chromium_presubmit/bu...)

[ccameron, 2014-07-18 22:08:51]

The CQ bit was checked by ccameron@chromium.org

[commit-bot: I haz the power, 2014-07-18 22:10:42]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ccameron@chromium.org/399213003/60001

[commit-bot: I haz the power, 2014-07-18 22:27:57]

Change committed as 284224