WebUI: Make WebUIPolymer2 flag work for optimize_webui=true, part 3.

In this CL updating:
 - chrome://history
 - chrome://print
 - chrome://settings

This adds some additional size to the binary, since both Polymer 1 and 2 HTML
bundles are included. This is temporary and the Polymer 1 version will be
removed once the migration is completed

Bug: 862472
Change-Id: Ia77a01b730630ab04a34483c7f0a53358501ceed
Reviewed-on: https://chromium-review.googlesource.com/1155834
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579663}
9 files changed