Changed XRHandedness enum to 'none' from empty string

Bug: 933411
Change-Id: I7e698846e7c733c15a82bd9079855df1e2d5abf4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1504223
Reviewed-by: Brian Sheedy <bsheedy@chromium.org>
Reviewed-by: Klaus Weidner <klausw@chromium.org>
Commit-Queue: Brandon Jones <bajones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638243}
5 files changed