mustash: Connect ash system tray "show settings" items to chrome over mojo

ash/common/system/chromeos/supervised/tray_supervised_user.cc

Index: ash/common/system/chromeos/supervised/tray_supervised_user.cc
diff --git a/ash/common/system/chromeos/supervised/tray_supervised_user.cc b/ash/common/system/chromeos/supervised/tray_supervised_user.cc
index a048ef59f6ae01be6773b3f62ce951174de918c3..e4d13f3390571e0710aaf62289d53e3bdbdda04d 100644
--- a/ash/common/system/chromeos/supervised/tray_supervised_user.cc
+++ b/ash/common/system/chromeos/supervised/tray_supervised_user.cc
@@ -69,7 +69,8 @@ void TraySupervisedUser::DestroyDefaultView() {
 }
 
 void TraySupervisedUser::OnViewClicked(views::View* sender) {
-  WmShell::Get()->system_tray_delegate()->ShowSupervisedUserInfo();
+  // TODO(antrim): find out what should we show in this case.

[msw, 2016/09/27 20:14:33]

nit: cc antrim? remove/update bug citation (it's closed...)

[James Cook, 2016/09/27 20:48:58]

Removed the bug number and pinged the bug + kuscher. antrim doesn't work on
chrome anymore.

+  // http://crbug.com/229762
 }
 
 void TraySupervisedUser::UpdateAfterLoginStatusChange(LoginStatus status) {