Transfer SecurityOrigin overrides to Workers.

Should a Document be operating with a SecurityOrigin that grants
(powerful) abilities like disabling same-origin policy or allows
file access, have those transfer over to any new Workers created.

R=horo,mkwst,jochen
BUG=254993

Review URL: https://codereview.chromium.org/594803002

git-svn-id: svn://svn.chromium.org/blink/trunk@182897 bbb929c8-8fbe-4397-9dbb-9b2b20218538
23 files changed