Include it only in the .cc files where it's needed.

R=fschneider@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/8117001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9506 ce2b1a6d-e550-0410-aec6-3dcde31c8c00