GTK: Check for null in bookmark bar drag received handler
GTK: Check for null in bookmark bar drag received handler

BUG=25491

Review URL: http://codereview.chromium.org/324003

git-svn-id: http://src.chromium.org/svn/trunk/src@29808 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 0d3bffdc1148240dace99ff5864286b1c0283ec4
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