GitLab

The GpuFeatureChecker callback is only called once, so convert to a
OnceCallback.

R=avi@chromium.org, reillyg@chromium.org

Bug: 1007763
Change-Id: I396324c692681f26e715bdd800153fbf8e38202b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1958187
Commit-Queue: danakj <danakj@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#723055}