Fixes crash in adding a menu item. As far as I can tell l10n_util::GetString(IDS_TASK_MANAGER) is returning "". Tony, myself and Rahul don't think this should be possible, yet we have crashes indicating otherwise. If IDS_TASK_MANAGER returns an emtpy string then menu derefs NULL and we crash.
Fixes crash in adding a menu item. As far as I can tell
l10n_util::GetString(IDS_TASK_MANAGER) is returning "". Tony, myself
and Rahul don't think this should be possible, yet we have crashes
indicating otherwise. If IDS_TASK_MANAGER returns an emtpy string then
menu derefs NULL and we crash.

BUG=6206
TEST=no way to directly test this, instead just make sure menus still
     work.

Review URL: http://codereview.chromium.org/19434

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@8829 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser