GitLab

This CL applies a pull request submitted to Polymer to add RTL support
for paper-sliders.

BUG=696437
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2801193002
Cr-Commit-Position: refs/heads/master@{#462953}