Unofficial gardening. plugins/plugin-clip-subframe.html fails on OSX 10.8, too.

TBR=
BUG=

Review URL: https://codereview.chromium.org/22807009

git-svn-id: svn://svn.chromium.org/blink/trunk@156270 bbb929c8-8fbe-4397-9dbb-9b2b20218538