The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd

commit 1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd
Author: rbpotter <rbpotter@chromium.org>
Date: Fri Sep 14 02:22:10 2018

Print Preview Material Refresh: Add shadow below header

This CL changes CrContainerShadowBehavior to add the shadow before the
parent of the container element, instead of assuming the container is
a direct child of the elemenent implementing the behavior. This allows
the behavior to work correctly for Print Preview, and does not break
any existing implementers of this behavior (SettingsUI, various
extensions pages).

This also adds the behavior the print-preview-app along with the
specified styles for the shadow.

Bug:  883583 
Change-Id: I5cc110d33d00d5e4c84e8fafcc0e0bbc0a8e96a4
Reviewed-on: https://chromium-review.googlesource.com/1225861
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#591269}
[modify] https://crrev.com/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd/chrome/browser/resources/print_preview/new/BUILD.gn
[modify] https://crrev.com/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd/chrome/browser/resources/print_preview/new/app.html
[modify] https://crrev.com/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd/chrome/browser/resources/print_preview/new/app.js
[modify] https://crrev.com/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd/chrome/browser/resources/print_preview/new/header.html
[modify] https://crrev.com/1ec8c91f9cb1578b384aac26e644c57ae8e1a9dd/ui/webui/resources/cr_elements/cr_container_shadow_behavior.js

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/b1e0638a12b569791c0e64ec0fce247c6682c440

commit b1e0638a12b569791c0e64ec0fce247c6682c440
Author: rbpotter <rbpotter@chromium.org>
Date: Tue Sep 18 18:24:33 2018

Print Preview Refresh: use standard shadow styling

Match the Print Preview elevation shadow styling to the styling used in
other Web UI surfaces (extensions, settings).

Bug:  883583 
Change-Id: Ida1c4427e401de30c540c5109eb5b45e6b67f79f
Reviewed-on: https://chromium-review.googlesource.com/1227395
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#592117}
[modify] https://crrev.com/b1e0638a12b569791c0e64ec0fce247c6682c440/chrome/browser/resources/print_preview/new/app.html
[modify] https://crrev.com/b1e0638a12b569791c0e64ec0fce247c6682c440/chrome/browser/resources/print_preview/new/header.html