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Specifically porting:
 - cr-button
 - cr-checkbox
 - cr-toast
 - cr-toggle
 - cr-view-manager
 - md-select, shared-style, hidden-style styles
 - shared icons

Repro:
 - Add optimize_webui=false flag.
 - Go to chrome://print/polymer3/demo.html.
 - See working cr-* elements, styles, icons.
 - Open Devtools console.
 - No HTML imports warnings should exist.

Bug: 965770
Change-Id: I1eec3c588a155ce32477cbd74cbd0a4864fb3ba3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1626665
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683221}