Remove usages of deprecated v8 apis in extensions in chrome/

BUG=324225
R=eisinger@google.com, jochen@chromium.org

Review URL: https://codereview.chromium.org/94163004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237790 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237790