GitLab

Update template expressions replacement to use the new HTML template
start and end markers instead of looking for _template: html` and `,.
This allows some simplification of the logic and will enable i18n
replacements in JS files using class based Polymer 3 syntax, since
the autogeneration code adds these markers to the start and end of
HTML templates at build time regardless of syntax.

Also modifying some existing tests to use class based syntax, and
adding more tests for less common cases and for mixed class/legacy
syntax.

Bug: 1023841
Change-Id: I764ee18621bc526f259b7b970e6008e0de220711
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1935609Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Commit-Queue: Rebekah Potter <rbpotter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#719259}