Crash on nested IPC handlers in PrintWebViewHelper

Crash on nested IPC handlers in PrintWebViewHelper

Class is not designed to handle nested IPC. Regular flows also does not
expect them. Still during printing of plugging them may show message
boxes and start nested message loops.
For now we are going just crash. If stats show us that this case is
frequent we will have to do something more complicated.

BUG=502562
Committed: https://crrev.com/8fa5a358cb32085b51daf92df8fd4a79b3931f81
Cr-Commit-Position: refs/heads/master@{#338100}

[Vitaly Buka (NO REVIEWS), 2015-07-08 20:48:15]

vitalybuka@chromium.org changed reviewers:
+ inferno@chromium.org, thestig@chromium.org

[Vitaly Buka (NO REVIEWS), 2015-07-08 20:48:21]

The CQ bit was checked by vitalybuka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-08 20:49:24]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1228693002/1

[Vitaly Buka (NO REVIEWS), 2015-07-08 20:49:25]

vitalybuka@chromium.org changed reviewers:
+ raymes@chromium.org

[commit-bot: I haz the power, 2015-07-08 21:36:43]

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

[commit-bot: I haz the power, 2015-07-08 21:36:44]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

(exceeded global retry quota)

[raymes, 2015-07-09 01:57:55]

On 2015/07/08 21:36:44, commit-bot: I haz the power wrote:
> Dry run: Try jobs failed on following builders:
>   win_chromium_rel_ng on tryserver.chromium.win (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)
> 
> (exceeded global retry quota)

It's not exactly clear to me why re-entrancy occurs here. Do you know? I think
it would be good to add a comment about this.

[Vitaly Buka (NO REVIEWS), 2015-07-09 05:54:33]

https://codereview.chromium.org/1228693002/diff/20001/components/printing/ren...
File components/printing/renderer/print_web_view_helper.cc (right):

https://codereview.chromium.org/1228693002/diff/20001/components/printing/ren...
components/printing/renderer/print_web_view_helper.cc:885: // script to show
message box http://crbug.com/502562. In that moment browser
Added explanation.

[Vitaly Buka (NO REVIEWS), 2015-07-09 05:54:39]

The CQ bit was checked by vitalybuka@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-07-09 05:54:53]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1228693002/40001

[raymes, 2015-07-09 06:37:42]

Thanks for adding the comment. It would be nice to know in what situations we
run a nested message loop that can trigger printing and handle those better.

I'm ok with this for now though, to avoid the UAF.

lgtm

https://codereview.chromium.org/1228693002/diff/40001/components/printing/ren...
File components/printing/renderer/print_web_view_helper.cc (right):

https://codereview.chromium.org/1228693002/diff/40001/components/printing/ren...
components/printing/renderer/print_web_view_helper.cc:888: // When this happened
message handling function may choose to ignore message
nit: merge this onto the previous line

[commit-bot: I haz the power, 2015-07-09 06:39:44]

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

[commit-bot: I haz the power, 2015-07-09 06:39:45]

Dry run: This issue passed the CQ dry run.

[Vitaly Buka (NO REVIEWS), 2015-07-09 17:56:00]

https://codereview.chromium.org/1228693002/diff/40001/components/printing/ren...
File components/printing/renderer/print_web_view_helper.cc (right):

https://codereview.chromium.org/1228693002/diff/40001/components/printing/ren...
components/printing/renderer/print_web_view_helper.cc:888: // When this happened
message handling function may choose to ignore message
On 2015/07/09 06:37:42, raymes wrote:
> nit: merge this onto the previous line

Done.

[Vitaly Buka (NO REVIEWS), 2015-07-09 17:56:04]

The CQ bit was checked by vitalybuka@chromium.org

[Vitaly Buka (NO REVIEWS), 2015-07-09 17:56:04]

The patchset sent to the CQ was uploaded after l-g-t-m from raymes@chromium.org
Link to the patchset: https://codereview.chromium.org/1228693002/#ps60001
(title: " ")

[commit-bot: I haz the power, 2015-07-09 17:57:37]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1228693002/60001

[commit-bot: I haz the power, 2015-07-09 18:45:51]

Committed patchset #4 (id:60001)

[commit-bot: I haz the power, 2015-07-09 18:46:53]

Patchset 4 (id:??) landed as
https://crrev.com/8fa5a358cb32085b51daf92df8fd4a79b3931f81
Cr-Commit-Position: refs/heads/master@{#338100}