Firefox3Importer crashes on importing empty folder from Bookmarks Menu.
Firefox3Importer crashes on importing empty folder from Bookmarks Menu.

In ImportBookmarks(), empty folders generate invalid TemplateURL objects.
SetKeywords() was called with this invalid argument.

BUG=73073
TEST=pass unit_tests
Review URL: http://codereview.chromium.org/6469045

git-svn-id: http://src.chromium.org/svn/trunk/src@76259 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ec7c646939f457cd6f54e4dc061d4231e1c75176
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