Access to Chrome via the System Tray should go through the User Manager.

chrome/browser/ui/views/profiles/user_manager_view.h

Index: chrome/browser/ui/views/profiles/user_manager_view.h
diff --git a/chrome/browser/ui/views/profiles/user_manager_view.h b/chrome/browser/ui/views/profiles/user_manager_view.h
index d9be1d38ae22510560fc0b642544d8682f84f776..6fe9739cfe52056be72d26220d9b674b39c99607 100644
--- a/chrome/browser/ui/views/profiles/user_manager_view.h
+++ b/chrome/browser/ui/views/profiles/user_manager_view.h
@@ -22,9 +22,11 @@ class UserManagerView : public views::DialogDelegateView {
   // Shows the User Manager or re-activates an existing one, focusing the
   // profile given by |profile_path_to_focus|. Based on the value of
   // |tutorial_mode|, a tutorial could be shown, in which case
-  // |profile_path_to_focus| is ignored.
+  // |profile_path_to_focus| is ignored. After a profile is opened, execute the
+  // |profile_open_action|.
   static void Show(const base::FilePath& profile_path_to_focus,
-                   profiles::UserManagerTutorialMode tutorial_mode);
+                   profiles::UserManagerTutorialMode tutorial_mode,
+                   profiles::UserManagerProfileSelected profile_open_action);
 
   // Hide the User Manager.
   static void Hide();