GitLab

Best to not try to add a string to a set without converting the set to
a string first.

R=dpranke@chromium.org

Bug: 713137
Change-Id: Id4c632b1f944fcafdd046983b1ddd4678c44928f
Reviewed-on: https://chromium-review.googlesource.com/564939Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Commit-Queue: bratell at Opera <bratell@opera.com>
Cr-Commit-Position: refs/heads/master@{#486706}