It takes 40-60 seconds on Windows Debug and Linux Debug. http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=nspector%2Fprofiler%2Fdetailed-heapshots-summary.html&group=%40ToT%20-%20chromium.org
Thanks for reporting. I'll fix it.
Fixed together with https://bugs.webkit.org/show_bug.cgi?id=58011 in http://trac.webkit.org/changeset/83286