GitLab

This adds a SandboxSeccompBpf class to centralize Seccomp BPF sandbox
policies inside of content/

LinuxSandbox is the only user of this class and Linux sandboxing is now fully
unified through LinuxSandbox.

BUG=
NOTRY=true

Review URL: https://chromiumcodereview.appspot.com/10843042

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149738 0039d316-1c4b-4281-b951-d872f2087c98