GitLab

Need to wrap <style is="custom-style"> with <custom-style> such that styling
works both in Polymer 1 and Polymer 2.

Bug: 739532,896507
Change-Id: I40e4a1fa6ac071cc31268c5e86fa13a023a59490
Reviewed-on: https://chromium-review.googlesource.com/c/1287258Reviewed-by: Scott Chen <scottchen@chromium.org>
Commit-Queue: Demetrios Papadopoulos <dpapad@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600868}