[Win10 sandbox mitigations] MITIGATION_NONSYSTEM_FONT_DISABLE adjustment.

Enable MITIGATION_NONSYSTEM_FONT_DISABLE mitigation
in child processes only when Direct Write is enabled (not for GDI).
This CL follows https://codereview.chromium.org/1666753002.

R=wfh@chromium.org,jschuh@chromium.org
BUG=504006,586291

Review URL: https://codereview.chromium.org/1720643002

Cr-Commit-Position: refs/heads/master@{#377110}
1 file changed