Convert PageGroup to using std::unique_ptr
Created attachment 213123 [details] Patch
Comment on attachment 213123 [details] Patch Attachment 213123 [details] did not pass efl-wk2-ews (efl-wk2): Output: http://webkit-queues.appspot.com/results/2891200
Committed r156751: <http://trac.webkit.org/changeset/156751>