Fix a crash related to null BrowserPluginGuest on Mac

Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied together and
it is possible for BrowserPluginGuest to be destroyed sooner than RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Committed: https://crrev.com/8f4b865fb7acb1b755c6c97650fa234106f59e14
Cr-Commit-Position: refs/heads/master@{#439719}

[EhsanK, 2016-12-20 02:08:21]

Description was changed from

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
==========

to

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
==========

[EhsanK, 2016-12-20 02:09:20]

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

[commit-bot: I haz the power, 2016-12-20 02:09:45]

Dry run: 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, 2016-12-20 03:51:08]

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

[commit-bot: I haz the power, 2016-12-20 03:51:09]

Dry run: This issue passed the CQ dry run.

[EhsanK, 2016-12-20 04:20:26]

ekaramad@chromium.org changed reviewers:
+ avi@chromium.org

[EhsanK, 2016-12-20 04:20:27]

Hi Avi. Could you please review this CL?

Thanks!

[Avi (use Gerrit), 2016-12-20 04:41:01]

lgtm

Wow.

Hope we can get this cleaned up with OOPIFs soon...

[EhsanK, 2016-12-20 05:44:58]

On 2016/12/20 04:41:01, Avi wrote:
> lgtm
> 
> Wow.
> 
> Hope we can get this cleaned up with OOPIFs soon...

Thanks!

Yes. avallee@ will be working on reworking MimeHandlerViewGuest based on OOPIF.
I still have not found a reliable repro of this crash but this is what is
happening.

I will keep poking at it to see what really is the issue with Mac that caused
this.

[EhsanK, 2016-12-20 05:45:16]

The CQ bit was checked by ekaramad@chromium.org

[commit-bot: I haz the power, 2016-12-20 05:45:32]

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, 2016-12-20 05:48:58]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1482212716266320, "parent_rev":
"4b702779c1dcc9e319c84bff65dd108034cf3328", "commit_rev":
"f9c1a29d8b4a03183bb19359d9d5a0127eba88ff"}

[commit-bot: I haz the power, 2016-12-20 05:49:29]

Description was changed from

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation
==========

to

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2588233002
==========

[commit-bot: I haz the power, 2016-12-20 05:49:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-20 05:53:56]

Description was changed from

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2588233002
==========

to

==========
Fix a crash related to null BrowserPluginGuest on Mac

The lifetimes of RenderWidgetHostViewGuest and BrowserPluginGuest are not tied
together and
it is possible for BrowserPluginGuest to be destroyed sooner than
RenderWidgetHostViewGuest.

This CL will check for |guest_| null-ness before getting owner's
RenderWidgetHostView from
it.

BUG=674417
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Committed: https://crrev.com/8f4b865fb7acb1b755c6c97650fa234106f59e14
Cr-Commit-Position: refs/heads/master@{#439719}
==========

[commit-bot: I haz the power, 2016-12-20 05:53:57]

Patchset 1 (id:??) landed as
https://crrev.com/8f4b865fb7acb1b755c6c97650fa234106f59e14
Cr-Commit-Position: refs/heads/master@{#439719}