Print Preview Destinations Dropdown: Polymer changes

Adding a createIcon() method to IronIconsetSvg, to allow icons in
the iconset to be retrieved and added inline outside of iron-icons. This
is required for Print Preview to use the destination icons in the
background of a dropdown menu while keeping the icons in its iconset.

Bug: 920056
Change-Id: I8f8b68c190cec8b31d9dc5d91adf182adca796f8
Reviewed-on: https://chromium-review.googlesource.com/c/1405457
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622175}
3 files changed