Previously it was owned by pointer but now it is not necessary and we can own it by value.

BUG=none
TEST=none

Review URL: https://chromiumcodereview.appspot.com/9969197

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11351 ce2b1a6d-e550-0410-aec6-3dcde31c8c00