gpu_info_util: fix a DeviceInfo leak on Windows BUG=angleproject:1874 Change-Id: I382e306ce0c27a81e0d746fb9922fa12988927d4 Reviewed-on: https://chromium-review.googlesource.com/469230 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Corentin Wallez <cwallez@chromium.org>