GTK: tweak where widget-anchored menus appear.
GTK: tweak where widget-anchored menus appear.

BUG=15443
TEST=see bug. Page/app menus + download item menus + bookmark bar menus should be fixed.

Review URL: http://codereview.chromium.org/672024

git-svn-id: http://src.chromium.org/svn/trunk/src@40978 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ab5618666f26c412d25ea9c325555a801e7e0b86
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