Fix private tab settings
Fix private tab settings

Fix #6339

Auditors: da39a3ee5e6b4b0d3255bfef95601890afd80709@bridiver

pmkary/braver,darkdh/browser-laptop,pmkary/braver,darkdh/browser-laptop,luixxiul/browser-laptop,timborden/browser-laptop,darkdh/browser-laptop,diasdavid/browser-laptop,pmkary/braver,timborden/browser-laptop,luixxiul/browser-laptop,pmkary/braver,diasdavid/browser-laptop,timborden/browser-laptop,timborden/browser-laptop,diasdavid/browser-laptop,luixxiul/browser-laptop,diasdavid/browser-laptop,luixxiul/browser-laptop,darkdh/browser-laptop