Fix a crash on closing tab while the plugin settings bubble is visible

Fix a crash on closing tab while the plugin settings bubble is visible

Add a null check instead of DCHECK() for web contents since it can be NULL
and cause a crash on debug builds, if the tab is closed while the plugin
settings bubble is visible and the setting was changed to Allow plugins.

BUG=440410
Committed: https://crrev.com/7521caae75e0194344e4b0fd5fa85660eedeaf5a
Cr-Commit-Position: refs/heads/master@{#308299}

[babu, 2014-12-09 14:45:29]

sudarsana.nagineni@intel.com changed reviewers:
+ markusheintz@chromium.org

[Lei Zhang, 2014-12-11 18:32:46]

thestig@chromium.org changed reviewers:
+ gbillock@chromium.org, thestig@chromium.org

[Lei Zhang, 2014-12-11 18:32:46]

Greg, do you remember why some of the OnCustomLinkClicked() methods in
content_setting_bubble_model.cc have a DCHECK(web_contents()) while others check
it and return?

[Greg Billock, 2014-12-11 20:06:21]

No, I don't think I ever learned that. :-(

On Thu, Dec 11, 2014 at 10:32 AM, <thestig@chromium.org> wrote:

> Greg, do you remember why some of the OnCustomLinkClicked() methods in
> content_setting_bubble_model.cc have a DCHECK(web_contents()) while
> others check
> it and return?
>
> https://codereview.chromium.org/791633003/
>

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[markusheintz_, 2014-12-12 09:42:49]

On 2014/12/11 20:06:21, Greg Billock wrote:
> No, I don't think I ever learned that. :-(
> 
> On Thu, Dec 11, 2014 at 10:32 AM, <mailto:thestig@chromium.org> wrote:
> 
> > Greg, do you remember why some of the OnCustomLinkClicked() methods in
> > content_setting_bubble_model.cc have a DCHECK(web_contents()) while
> > others check
> > it and return?
> >
> > <crxref style="background-image:
url(chrome-extension://ppnlfijacbhfpjgkafbeiaklmgoljooo/res/type/codereview.png);">https://codereview.chromium.org/791633003/</crxref>
> >
> 
> To unsubscribe from this group and stop receiving emails from it, send an
email
> to mailto:chromium-reviews+unsubscribe@chromium.org.

While the tab is opened or closed it can happen that the web content does not
exist yet or not exist anymore. To prevent chrome from crashing the DCHECKs
where replaced with if statements. The CL description describes this.

[markusheintz_, 2014-12-12 09:43:09]

LGTM after addressing my comement

https://codereview.chromium.org/791633003/diff/1/chrome/browser/ui/content_se...
File chrome/browser/ui/content_settings/content_setting_bubble_model.cc (right):

https://codereview.chromium.org/791633003/diff/1/chrome/browser/ui/content_se...
chrome/browser/ui/content_settings/content_setting_bubble_model.cc:500: if
(!web_contents())
Please add a comment above this line that explains why this is necessary.

[babu, 2014-12-12 12:02:31]

Thanks for review!

On 2014/12/12 09:43:09, markusheintz_ wrote:
> LGTM after addressing my comement
> 
>
https://codereview.chromium.org/791633003/diff/1/chrome/browser/ui/content_se...
> File chrome/browser/ui/content_settings/content_setting_bubble_model.cc
(right):
> 
>
https://codereview.chromium.org/791633003/diff/1/chrome/browser/ui/content_se...
> chrome/browser/ui/content_settings/content_setting_bubble_model.cc:500: if
> (!web_contents())
> Please add a comment above this line that explains why this is necessary.

Done.

[babu, 2014-12-14 16:57:28]

The CQ bit was checked by sudarsana.nagineni@intel.com

[commit-bot: I haz the power, 2014-12-14 16:57:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/791633003/20001

[commit-bot: I haz the power, 2014-12-14 17:48:45]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-12-14 17:49:33]

Patchset 2 (id:??) landed as
https://crrev.com/7521caae75e0194344e4b0fd5fa85660eedeaf5a
Cr-Commit-Position: refs/heads/master@{#308299}