Add SeccompSupportDetector for Android.

This class will report to UMA the Android kernel version and the level of kernel
support for seccomp-bpf sandboxing.

BUG=468455

Review URL: https://codereview.chromium.org/1018953004

Cr-Commit-Position: refs/heads/master@{#321451}
13 files changed