[Win10 sandbox mitigations] Enable the 3 new mitigations.

Turning on 3 new mitigations for all child processes (pre-startup).
This CL follows https://codereview.chromium.org/1626623003/.

R=wfh@chromium.org
BUG=504006

Review URL: https://codereview.chromium.org/1666753002

Cr-Commit-Position: refs/heads/master@{#373346}
1 file changed