GitLab

If the Chrome Cleaner requires a reboot of the machine to complete the
cleanup operation, Chrome will need to offer a reboot to the user. In
order to initiate a shutdown + restart, Chrome needs to acquire
SeShutdownPrivilege. The ScopedTokenPrivilege from
chrome/installer/setup/setup_util provides that functionality. This CL
moves it to chrome/installer/util where it can be used by both Chrome
and Setup.

BUG=728136

Review-Url: https://codereview.chromium.org/2925383002
Cr-Commit-Position: refs/heads/master@{#478357}