This method is c++11 only and caused a build breakage on Mac.

BUG=angle:773

Change-Id: Ib362b8d577aa85b9d6d2b8b87840ec5197240cf2
Reviewed-on: https://chromium-review.googlesource.com/241010Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>