am cfd0bafd: Merge changes Iaa7bc042,Icc312fc9,I50ba06ed into honeycomb

* commit 'cfd0bafdebf1fccd3f5a0baed5cad8a539546e9b':
  Make keyguard also ask to turn the back button off, now that it is controlled separately.
  Allow independent control of the back and the other navigation buttons.
  Allow the status bar disable flags to be used as View's system ui visibility fields.