Null out a field in the RenderFrameHostImpl dtor.

Null out a field in the RenderFrameHostImpl dtor.

This will be useful as a signal in crash dumps, indicating that the dtor
has run.

BUG=438951
Committed: https://crrev.com/fe570b5e9a76a536685695e44f1ca11903d5aea2
Cr-Commit-Position: refs/heads/master@{#307950}

[ncarter (slow), 2014-12-10 18:30:03]

nick@chromium.org changed reviewers:
+ estade@chromium.org

[ncarter (slow), 2014-12-10 18:30:03]

Evan, please have a look. This should provide some proof of whether the RFH
objects under examination have been freed.

[ncarter (slow), 2014-12-10 21:16:38]

nick@chromium.org changed reviewers:
+ creis@chromium.org

[ncarter (slow), 2014-12-10 21:16:38]

creis@chromium.org: need you as OWNER

[Evan Stade, 2014-12-10 22:02:19]

thanks for investigating this so thoroughly. lgtm

https://codereview.chromium.org/794673002/diff/1/content/browser/frame_host/r...
File content/browser/frame_host/render_frame_host_impl.cc (right):

https://codereview.chromium.org/794673002/diff/1/content/browser/frame_host/r...
content/browser/frame_host/render_frame_host_impl.cc:181:
swapout_event_monitor_timeout_.reset();
sorta surprised scoped_ptr doesn't already null out the pointer in its
destructor

[Charlie Reis, 2014-12-10 22:04:27]

LGTM

[ncarter (slow), 2014-12-10 22:09:50]

https://codereview.chromium.org/794673002/diff/1/content/browser/frame_host/r...
File content/browser/frame_host/render_frame_host_impl.cc (right):

https://codereview.chromium.org/794673002/diff/1/content/browser/frame_host/r...
content/browser/frame_host/render_frame_host_impl.cc:181:
swapout_event_monitor_timeout_.reset();
On 2014/12/10 22:02:18, Evan Stade wrote:
> sorta surprised scoped_ptr doesn't already null out the pointer in its
> destructor

I was surprised too, but it turns out that ~scoped_ptr_impl just invokes the
deleter (versus calling reset(), which would write nullptr to the ptr field).
Relevant lines:

https://code.google.com/p/chromium/codesearch#chromium/src/base/memory/scoped...

https://code.google.com/p/chromium/codesearch#chromium/src/base/memory/scoped...

[ncarter (slow), 2014-12-10 22:16:51]

The CQ bit was checked by nick@chromium.org

[commit-bot: I haz the power, 2014-12-10 22:18:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/794673002/1

[commit-bot: I haz the power, 2014-12-11 01:07:38]

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

[commit-bot: I haz the power, 2014-12-11 01:07:39]

Try jobs failed on following builders:
  linux_chromium_asan_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_...)

[ncarter (slow), 2014-12-11 18:40:13]

The CQ bit was checked by nick@chromium.org

[commit-bot: I haz the power, 2014-12-11 18:40:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/794673002/1

[commit-bot: I haz the power, 2014-12-11 19:36:44]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-12-11 19:37:29]

Patchset 1 (id:??) landed as
https://crrev.com/fe570b5e9a76a536685695e44f1ca11903d5aea2
Cr-Commit-Position: refs/heads/master@{#307950}