Linux sandbox: restrict *kill to the current process.

Restrict tgkill(2) and kill(2) to the current process, forbid tkill.

BUG=367986
R=jorgelo@chromium.org

Review URL: https://codereview.chromium.org/258073008

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@266926 0039d316-1c4b-4281-b951-d872f2087c98
7 files changed