The phones and tablets currently in use are much slower that desktop
and laptop machines for which the current heuristics have been tuned.
Review URL: http://codereview.chromium.org/8757017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10103 ce2b1a6d-e550-0410-aec6-3dcde31c8c00