The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/079e92c3bd4a131e004cd3ea5a30ec0509e991d6

commit 079e92c3bd4a131e004cd3ea5a30ec0509e991d6
Author: Lei Zhang <thestig@chromium.org>
Date: Sat Jul 21 00:36:07 2018

Specify the right doc type for the PDF compositor.

When printing PDFs, the data type should be set to PDF. Normally this is
not an issue because the renderer will just send back PDF data anyway.
However, on PDF rendering failure, it defaults to the doc type to figure
out what to generate for the dummy data.

BUG= 865793 

Change-Id: I807688d07baa299af4319569a98ab2e07319cf39
Reviewed-on: https://chromium-review.googlesource.com/1144783
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577045}
[modify] https://crrev.com/079e92c3bd4a131e004cd3ea5a30ec0509e991d6/components/printing/browser/print_manager_utils.cc

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/7996d9622f4bd1a72bddc58b24fdab366b1976e4

commit 7996d9622f4bd1a72bddc58b24fdab366b1976e4
Author: Lei Zhang <thestig@chromium.org>
Date: Sat Jul 21 00:39:17 2018

Validate data in PrintPreviewDataStore.

It should be storing PDF data and not MSKP. Adjust tests to pass.

BUG= 865793 

Change-Id: Ib28e9c0a1579dd05d9d500bd7473103828c30079
Reviewed-on: https://chromium-review.googlesource.com/1144781
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577047}
[modify] https://crrev.com/7996d9622f4bd1a72bddc58b24fdab366b1976e4/chrome/browser/printing/print_preview_data_service.cc
[modify] https://crrev.com/7996d9622f4bd1a72bddc58b24fdab366b1976e4/chrome/browser/ui/webui/print_preview/print_preview_ui_unittest.cc