Patch for /usr/share/applications/google-chrome.desktop:
108c108 < Exec=/opt/google/chrome/google-chrome %U --- > Exec=/opt/google/chrome/google-chrome %U --incognito 114c114 < X-Ayatana-Desktop-Shortcuts=NewWindow;NewIncognito --- > X-Ayatana-Desktop-Shortcuts=NewIncognito;NewWindow