Fix memory leak of PreviewModeClient in PDF

Fix memory leak of PreviewModeClient in PDF

Previously, in print preview, we would construct a new PreviewModeClient and
pass it to the PDFEngine, however the PDFEngine does not maintain ownership
of the client passed in. Instead OutOfProcessInstance should maintain ownership
which is fixed by this CL.

BUG=522286
Committed: https://crrev.com/cf7b9bfd81a7f2690c80deb46d35833acb692975
Cr-Commit-Position: refs/heads/master@{#347652}

[raymes, 2015-09-07 02:51:15]

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

[raymes, 2015-09-07 02:51:22]

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

[commit-bot: I haz the power, 2015-09-07 02:51:30]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1323943011/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1323943011/1

[commit-bot: I haz the power, 2015-09-07 03:36:11]

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

[commit-bot: I haz the power, 2015-09-07 03:36:12]

Dry run: This issue passed the CQ dry run.

[Lei Zhang, 2015-09-07 19:31:46]

https://codereview.chromium.org/1323943011/diff/1/pdf/out_of_process_instance.h
File pdf/out_of_process_instance.h (right):

https://codereview.chromium.org/1323943011/diff/1/pdf/out_of_process_instance...
pdf/out_of_process_instance.h:264: scoped_ptr<PreviewModeClient>
preview_client_;
Doesn't member destruction go bottom up? i.e. as is, |preview_client_| will be
freed before |preview_engine_|, though |preview_engine_| still has a pointer to
|preview_client_|.

[raymes, 2015-09-07 23:59:00]

https://codereview.chromium.org/1323943011/diff/1/pdf/out_of_process_instance.h
File pdf/out_of_process_instance.h (right):

https://codereview.chromium.org/1323943011/diff/1/pdf/out_of_process_instance...
pdf/out_of_process_instance.h:264: scoped_ptr<PreviewModeClient>
preview_client_;
On 2015/09/07 19:31:46, Lei Zhang wrote:
> Doesn't member destruction go bottom up? i.e. as is, |preview_client_| will be
> freed before |preview_engine_|, though |preview_engine_| still has a pointer
to
> |preview_client_|.

Done.

[raymes, 2015-09-07 23:59:08]

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

[commit-bot: I haz the power, 2015-09-07 23:59:13]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1323943011/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1323943011/20001

[Lei Zhang, 2015-09-08 00:23:58]

lgtm

[commit-bot: I haz the power, 2015-09-08 00:52:14]

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

[commit-bot: I haz the power, 2015-09-08 00:52:15]

Dry run: This issue passed the CQ dry run.

[raymes, 2015-09-08 01:07:08]

The CQ bit was checked by raymes@chromium.org

[commit-bot: I haz the power, 2015-09-08 01:07:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1323943011/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1323943011/20001

[commit-bot: I haz the power, 2015-09-08 01:11:20]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-08 01:12:03]

Patchset 2 (id:??) landed as
https://crrev.com/cf7b9bfd81a7f2690c80deb46d35833acb692975
Cr-Commit-Position: refs/heads/master@{#347652}