on a real web application loaded in the test shell.

Also implemented output of JSON-encoded call stacks for profiler
prototype.

Review URL: http://codereview.chromium.org/56064

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@1646 ce2b1a6d-e550-0410-aec6-3dcde31c8c00