Add a presubmit check to catch usage of Singleton<T> in header files.
Add a presubmit check to catch usage of Singleton<T> in header files.

BUG=65298
TEST=none

Review URL: http://codereview.chromium.org/5753006

git-svn-id: http://src.chromium.org/svn/trunk/src@69129 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 7a1df12f213178de559335e1e842a1c698e51e40
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