This is to make possible enabling usage of the new profiling subsystem
in Chromium without much hassle. The idea is pretty simple: unless the
new profiling API is used, all works as usual, as soon as Chromium
starts to use the new API, it will work too.

Review URL: http://codereview.chromium.org/1635005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4382 ce2b1a6d-e550-0410-aec6-3dcde31c8c00