GitLab

Adds a wrapper to contain building proc_thread_attribute_* and to
provide storage for pointed-at items for call to
CreateProcessAsUserW().

This does not change functionality, but moves code from target_services
into a helper.

Bug: 1050359
Change-Id: I3d25e028638b2ea6f2917de1154be7a99fdf5971
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2330736Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Alex Gough <ajgo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#794618}