Allow left clicks in the tab strip to initiate a drag of the window.
Allow left clicks in the tab strip to initiate a drag of the window.

Review URL: http://codereview.chromium.org/118127


git-svn-id: http://src.chromium.org/svn/trunk/src@17423 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 4a90e7c450776270dca5960e47cf1e243c715fa2
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