Simplify object printer declarations.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/23619010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16439 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Assert external strings in external string table. Remove TODOs.

R=hpayer@chromium.org
BUG=

Review URL: https://codereview.chromium.org/23567002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16440 ce2b1a6d-e550-0410-aec6-3dcde31c8c00