Simplified based on Michael's change Refactor how embedded pointers are visited. (9597)

Ported r9328 (bdc13b7)

BUG=
TEST=

Review URL: http://codereview.chromium.org/8106002
Patch from Paul Lind <pling44@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@9600 ce2b1a6d-e550-0410-aec6-3dcde31c8c00