Call addRef when creating a new Fence Sync object. BUG=angle:728 Change-Id: Iafd838c3ceb1a88afd4d3b0994e8d841945df499 Reviewed-on: https://chromium-review.googlesource.com/213142 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Brandon Jones <bajones@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>