Initial implementation of GetStackSample sampling profiler API.

The patch is based on https://codereview.chromium.org/578163002/#ps20001
made by gholap@chromium.org

LOG=N
BUG=v8:3490
R=bmeurer@chromium.org, yurys@chromium.org

Review URL: https://codereview.chromium.org/596533002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@24285 ce2b1a6d-e550-0410-aec6-3dcde31c8c00