Before creating a content setting, check that you actually *can* create it.
Before creating a content setting, check that you actually *can* create it.

BUG=none
TEST=none
R=danno@chromium.org

Review URL: http://codereview.chromium.org/3020018

git-svn-id: http://src.chromium.org/svn/trunk/src@53186 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 41b22f07c4f59fd05b27a816771b4270bf568e0a
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser