Prepare push to trunk.  Now working on version 3.21.18.

R=machenbach@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23669007

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16780 ce2b1a6d-e550-0410-aec6-3dcde31c8c00