linux: Use SimpleMenuModel::Delegate in TaskManager instead of MenuGtk::Delegate. 
linux: Use SimpleMenuModel::Delegate in TaskManager instead of MenuGtk::Delegate. 

BUG=31365
TEST=manually
patch by tfarina <thiago.farina [at] gmail>
original review ==> http://codereview.chromium.org/557072/show

Review URL: http://codereview.chromium.org/562040

git-svn-id: http://src.chromium.org/svn/trunk/src@38051 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: b6b0af71a24e7df04be5efacb3f4d5a0ab14029e
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