[Android] Define a baseline seccomp-bpf sandbox policy.

This is not used in production yet, since Android kernels do not have seccomp
mode two support, yet.

BUG=308763, 166704

Review URL: https://codereview.chromium.org/180783019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@263017 0039d316-1c4b-4281-b951-d872f2087c98
8 files changed