[ios] Fixed memory management in ExecuteScriptOnInterstitial.

[ios] Fixed memory management in ExecuteScriptOnInterstitial.

Autoreleasing inside the block made object released and caused a crash
on iOS9.

BUG=531721
Committed: https://crrev.com/5dd3785b5c294e45f766064723f6edd900900fdc
Cr-Commit-Position: refs/heads/master@{#435778}

[Eugene But (OOO till 7-30), 2016-12-01 23:38:17]

eugenebut@chromium.org changed reviewers:
+ jyquinn@chromium.org

[Jackie Quinn, 2016-12-01 23:46:16]

The CQ bit was checked by jyquinn@chromium.org

[Jackie Quinn, 2016-12-01 23:46:16]

lgtm

[commit-bot: I haz the power, 2016-12-01 23:46:46]

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, 2016-12-01 23:58:06]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1480635976213520, "parent_rev":
"01d65683e5740befa459408677435c810221ce31", "commit_rev":
"731f9e1bae5862a45705a586d82cdd84ea9de877"}

[commit-bot: I haz the power, 2016-12-01 23:58:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-02 00:00:42]

Description was changed from

==========
[ios] Fixed memory management in ExecuteScriptOnInterstitial.

Autoreleasing inside the block made object released and caused a crash
on iOS9.

BUG=531721
==========

to

==========
[ios] Fixed memory management in ExecuteScriptOnInterstitial.

Autoreleasing inside the block made object released and caused a crash
on iOS9.

BUG=531721

Committed: https://crrev.com/5dd3785b5c294e45f766064723f6edd900900fdc
Cr-Commit-Position: refs/heads/master@{#435778}
==========

[commit-bot: I haz the power, 2016-12-02 00:00:42]

Patchset 1 (id:??) landed as
https://crrev.com/5dd3785b5c294e45f766064723f6edd900900fdc
Cr-Commit-Position: refs/heads/master@{#435778}