OOP PDF: Use an object element for print preview instead of an embed.

OOP PDF: Use an object element for print preview instead of an embed.

This avoids the origin checking that prevents the PDF extension from
embedding the print-preview PDFs, which are served from the chrome
scheme.

BUG=437417
Committed: https://crrev.com/0a182576926c2b560035db3d53abd614a1423145
Cr-Commit-Position: refs/heads/master@{#306307}

[Sam McNally, 2014-12-01 00:05:14]

Patchset #1 (id:1) has been deleted

[Sam McNally, 2014-12-01 00:09:19]

Patchset #1 (id:20001) has been deleted

[Sam McNally, 2014-12-01 00:09:58]

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

[Lei Zhang, 2014-12-01 23:38:56]

lgtm since this is just a revert to the previous behavior for the print preview
case.

[Lei Zhang, 2014-12-01 23:38:59]

The CQ bit was checked by thestig@chromium.org

[commit-bot: I haz the power, 2014-12-01 23:39:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/766083002/40001

[commit-bot: I haz the power, 2014-12-02 00:32:34]

Committed patchset #1 (id:40001)

[commit-bot: I haz the power, 2014-12-02 00:33:21]

Patchset 1 (id:??) landed as
https://crrev.com/0a182576926c2b560035db3d53abd614a1423145
Cr-Commit-Position: refs/heads/master@{#306307}