Revert of rename UniquePersistent to Global (patchset #2 id:20001 of https://codereview.chromium.org/980173003/)

Reason for revert:
breaks arm compile

Original issue's description:
> rename UniquePersistent to Global
>
> BUG=
>
> Committed: https://crrev.com/3f5ae16c62b031ad572f750d81ffc71c5d6d1f9b
> Cr-Commit-Position: refs/heads/master@{#27011}

TBR=svenpanne@chromium.org,dcarney@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/983653002

Cr-Commit-Position: refs/heads/master@{#27012}