button_            56 ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc       button_(NULL) {
button_            16 chrome/browser/ui/gtk/hover_controller_gtk.cc       button_(button) {
button_            36 chrome/browser/ui/views/extensions/browser_action_overflow_menu_controller.cc         button_(button) {
button_            15 chrome/browser/ui/views/infobars/translate_message_infobar.cc       button_(NULL) {